Bob Z.

Soul high-flow cats are the best for the money and don't worry about the warranty (I didn't) and worst case is you can have them swapped out if something goes wrong but they are just cats. If you go with headers as well, which will give you a power bump along with better sound, you are taking more of a risk. Search the threads though and you will find a lot of warranty info regarding mods.

Robert Linton

Leave the car alone. It's a wonderful vehicle.

reacher

It's an even more wonderful vehicle after some cats and a tune. It completely transforms the car, and everything is an improvement with zero downsides to driveability. It feels so much better with that extra power.

rubycaymanr

Have mods that pushed horsepower to 480 at the wheels which is close to 570 Horsepower

Robert Linton

While I would question the actual HP improvement due to any exhaust modification (indeed, if you get any, it will not be noticeable to almost any driver), a proper tune should get you something. Having said that, most drivers in most driving conditions will hardly ever notice it. So, again, I say leave the car alone. Other than louder noise giving physic HP, the real benefit will be minimal. Use the money for a family vacation or give to a good cause. The 911 is a wonderful machine. Too many people "mod" so they can say they did.

spdracerut

I would counter that a number of the aftermarket exhaust components (headers and cats) have measured and quantifiable gains from numerous sources resulting in both improved power and boost response. And people enjoy the hobby of car modifications. It can be seen as an extension of the Porsche build sheet with a bazillion options.

Robert Linton

If you take the factory exhaust and any aftermarket unit on absolutely equal cars under absolutely equal conditions (i.e., absolutely everything) the likelihood of getting much more than 5 extra HP is minimal. And I would opine that the average driver cannot feel even 10 HP let alone 5.

Bob Z.

But the sound is sooooooo much better!

Robert Linton

No question, the sound can be modified. How it sounds is personal preference.

Robert Linton

And, of course, the weight can be reduced. But, again, I would question if in reality the average driver would notice 50 or 60 lbs, other than in his/her mind.

achtung6

Not a performance mod but one that can provide a much better use experience. The T-design memory module that lets you defeat engine auto start-stop.
This should have been my first mod.

Robert Linton

Never heard of it. Very interesting. Thank you

reacher

I wish it instead put the car in the last mode you had it in. I never drive in normal mode, so auto start/stop isn't an issue for me. I do wish I didn't have to switch it out of normal mode every time I start the car, though.

IXLR8

What mods?

And I'd want to see a BEFORE the mods graph. It along with your AFTER mods will show a gain. Why? Because you never know how well the Dyno is calibrated. I worked in a defense lab most of my life taking measurements.

You lost 90 HP going through transmissions and shafts? Your Dyno graph shows 488 HP at the "engine".

IXLR8

I am removing the RSR exhaust that came on my 993 and putting a stock system on. Love the sound of the cam driven chains. You can hear it on the opening scenes of LeMans when Steve is driving his 911.

As for mods, seat of the pants means squat! Noise does not mean power. lol

I'd sooner spend money on tires, brakes and suspension.