What do you consider overpowered and underprepared? I'm obviously new to this. My car is fairly stock. A previous owner installed Biltstein HD and HR springs at a lowered height. I added RS clutch and lwf, RS engine mounts and reinforced engine carrier. Next up is 3pt strut tower brace, cage (still undecided which route) seats and belts.

 

My son's DD and DE car is an E36 M3 - I had a welded half-cage professionally installed with seats and harnesses. I think this is the safest combination for a car that will also see regular street use. The factory seat belts were also retained for street use. A full cage can be a hazard when driven on the street since the driver has no helmet. At that point it becomes a dedicated track car only.
Your C4S looks very nice - another option you might want to consider is a dedicated track car such as a 944 or a E36 M3.

 

With a correct bolted mount cant you achieve very close to the same and possibly a better connection than a welded in cage? The bolt in if backed on the opposite side should create a stronger connection due to a better distribution of force around the plate couldn't it?

 

One thing that you may want to consider is that a "bolt-in" rollbar such as the Safety Devices one will still require drilling/welding on the car (capture plates for the roll bar to bolt to are required). As such, installation can be very expensive (the interior needs to be stripped out, the roll bar test fitted/adjusted, then the welding, and then everything needs to be put back together...the time adds up). Obviously safety isn't a place to cheap out, and I do think the Safety Devices bar is well designed, but you may want to call a few shops near you to get an estimate for installation before you make a final decision.

One other thing you may want to think about safety-wise that I didn't see mentioned above is a HANS device. I think if you're going to get harnesses, you may want to think about getting a HANS device because with your shoulders locked to the seats by the harnesses, your neck will be taking more force from your head accelerating in different directions.

 

For a track car the order of preference goes something like:
Custom cage
Welded prop cage
Bolted prop cage
Welded 4 point roll bar
Bolted 4 point roll bar
And way down the list - nothing at all.

If you are going for harnesses I would insist on a roll cage of some sort. Imagine being strapped bolt upright by your harness with the roof crushed in - not good.

For a dual purpose I would go with a roll bar and eliminate the likelihood of head contact. In my 911 I remove the front bars of its' SE bolt-in cage when it's not running the Targa.

I think the statements above about stripping your interior may be a little misleading. In my 911 (using the stable energies bar) I simply tested, marked and cut carpet, drilled and mounted (although later I did fully weld the 4 rear feet). In my 996 GT3 Using a DAS bar I took a similar approach (for the 996, DAS offered alternate feet that were bolted through the floor that I later used - but didn't need to).

Finally, to answer your question of someone else- cars' on track performance exceeded their safety way back before your 993 was built - probably around the time of the first RS. As an instructor it was something I often contemplated as some newby hurtled towards the guardrail in excess of 120MPH with very little idea of what they were doing or what would be the consequence of their failure to achieve.

 

Interesting I have just done this myself after my third DE. I spun out at Watkins Glen in August which prompted me to buy another 968 and not drive my queen. Went to Stable Energies for seats and a 6 point harness. Your right that a full roll cage is a pain to get into. Buying a design one chassis brace and having the car worked over at Provost. No one has mentioned a HANS device, but you might also consider this. I was extremely lucky, not injured and car not damaged even after hitting the wall. Yea I know, what! That was part of the luck. Luck can't be relied on, buy the best of what you can afford.

 

Sorry but wrecks do not work this way. (Unless someone drops you into a car crusher perhaps but then you got other issues to deal with) The same energy that is trying to drive the roof in is trying to drive You into the roof. Your body does not "duck down" in a blinding flash of violence it is slammed around rag doll like all over the inside of the car.

Agree as speeds increase impact deltas and energy levels do as well. Adding safety in is a good thing but you should also look at waht you are protecting yourself from.
Look at the numbers. by a vast margin on track impacts do not include meaningfull drivers compartment roof intrusion. With regards to a tin top Porsche besides offering a place to mount the shoulder straps roof intrusion protection is the only thing that a roll bar offers. A 4 point bar does not stiffen a 911. a 4 point bar does not protect the driver during a side impact. If you were to graph increased overall impact protection my contention is that there would be a large and steep jump with the addition of a 5 or 6 point system and a proper race type seat. This offers body and head and neck protection that is far better than a stock 3 point offers. Adding the roll bar to the above system utilizing a proper harness bar would only add a little bump on top of the already large increase the retention system adds but adds a lot of down sides in a day to day car. By the numbers. By the OMG fear factor it seems to be the same as com flights. Safest way ever to cover a mile by a long shot but more fear flight than the car ride to the airport.

All this blather is intneded to say one thing. Weight the addition of safety systems by real world numbers. All systems are a compromise. Look at what is likely and what up and downsides a system has and decide accordingly.

Then, Do it Right. Compromise is not just in the system but how the system is used and integrated with other systems. I see some full on race cars with setups that I would not drive in. Flexible unsupported seats with little if any upper body protection. lack of proper side netting. Poor egress design via tubing not fitted tightly to the existing body and or sharp window net clips jutting into the now much reduced exit area. Poorly installed fire systems that don't take impact energy into consideration. Poor cage design and fabrication that fails to use good methods such as clustering tubing into nodes and not having bends in tubing that should straight and much more.

One wreck I watched comes to mind. I looked over a 1995 993 that was in a strong rollover wad up at VIR some years ago. Driver was none worse for the wear other than some sore shoulders and some bumps here and there. many were touting that the roll bar saved the driver. One guy was loudly pointing out that a harness system only might have busted the drivers neck. I looked inside the car and saw that the roof headliner was not even scuffed and the roof metal never got near the bar. Crinkeled roof but not even near the driver. The seat system most likely saved the drivers life or greatly reduced the hurt. A 3 point system would have let the driver ragdoll far more than the installed race seat and 5 point system.

Don’t eschew the good for the slightly better.

 

I'm not sure I follow. By looking at the numbers I could argue that since the majority of accidents involve nothing more than gentle brushes with the wall then really I have no reason to even wear a seatbelt let alone update it. However that's not how I look at spending on safety. I personally believe that we should spend as much as we can afford on saving ourselves against as many of the worst case scenarios we can. We will never guarantee that we can survive anything without injury but let's do what we can to put the odds in our favor. I have seen an accident at a DE where the car was so top end damaged that it had to be cut off to extricate the driver. **** does happen and in this particular case if there had not been a full cage I don't know that the consequences wouldn't have been much worse. Anyway my point is that you may argue that rollover accidents are uncommon but until you can show me that they are so uncommon that they do not happen I'ld rather not take my chances.

Let me know if I misunderstood what ou were trying to say. I did find it a little hard to follow. I'm just a simple minded Australian.

 

Right mate. Improved body retention provides a large gain in wreck survivability with low street use impingement. Few wrecks involve drivers compartment roof intrusion. With a dual use car you need to weigh the street use to track use. Do the things that provide a good gain in safety without greatly diminishing street usability.

Keep in mind this is for a dual use car. Full track car = fire system, full cage, containment seat, right and left side nets, leg boards foot well drivers floor and rocker reinforcement and more.

 

I recently had a GMG World Challenge roll/harness bar installed in my 2003 C4S, along with Porsche GT3 seats (horrifically expensive, but in my view, the best seats for this car) and Schroth 6-pt harnesses. This seems to be a popular setup among NorCal DE/time trials friends. One more thing to consider: if you're getting harnesses put in, do it right and get the kind designed to work w/ a HANS device. You'll feel a lot safer and thus you'll go faster and have more fun.

 

The setup I have in my used-to-be-street/track now just street RSA I found a nice balance for DE/light time trial: A DAS bolt in rollbar (not the little one that spans between the rear belt mounts, but the full height one peice welded unit that sits on the frame rails and bolts through the seat belt pivots) a pair of Pole position seats, stock 3 point belts with the BreyKrausse clip in harness mounts and the Recaro/cup car sub strap mounting bar and two sets of shroth Profi harnesses. This is the minimum I would use with a Hans.

The shoulder straps were wrapped on the roll bar, the subs to the cup mount, and the lap belts clip in and out in five minutes. The sub bar keeps you from drilling the pan and relocating the DME. The seats mean no access to the rear but there is no safety issue with whacking your head on the rollbar, but it also limits the full range of the seat adjustability.

And completely self serving: I have a new never installed set of the clip in adapters ill sell at original price and ill ship free...

 

You're certainly getting the input on this one and the truth of the matter is that everyone is right.....for their own purposes. You have to decide what's going to make you comfrotable and give you confidence.

Under the heading of "For What it's Worth" I ran much the same setup as J Richard as I was coming up the skill ranks and found I was very confident in it and felt it was a reasonable trade off for still running on the street.
DAS 4 point Bolt in (was willing to scarifice rear seat access)
GT3 seats
Scroth 6 point harnesses
Hans
3 point belts still functional for street use

Having said that, there came a time when I felt the need for more protection and then I went to the full cage/stripped out interior and dedicated track car. I think you'll know it when you see it.

Good Luck with the process. No matter what you do, better seats and harnesses will improve your driving a lot.