I built it. I have the OE PSE on it, that's it. I don't really plan on doing anything else to this car.

I heard back from Randy and hes saying all the things I want to hear. Including this little tidbit:

Er - tunes "commensurate to your vehicles fitness and complimenting upgrades" by definition INCLUDE other engine modifications (upgrades). Pre-canned tunes that are a dime a dozen are the ones that will somewhat shorten the engine life or sacrifice some margin for error (if you get a bad batch of gas for example). If you've modded the engine, then a proper custom tune for your particular motor and mods may be able to get some more power without adversely affecting the longevity.

My 996TT had a GIAC chip almost immediately and $hitloads of trackways at Mosport and other tracks, ran flawlessly. Only upgrade was to modify the exhaust for better flow.

Did he also read you the line right above the one that mentions the $50K engine warranty, which states "Coverage is for 2 years or 32,000 kilometers from the original in-service date", and futhermore inform you that if your car still has some factory warranty left, their tune would void the same?

Nothing against Randy - he's a very decent bloke I know from the BMW CCA, but if any of you think that there is such a thing as a free lunch (i.e free horsepower), I have an amazing deal on some excellent Ronco knives and some miraculous fitness pills!

X2, and a great driver.

Maximum efficiency leave no room for error.

That isn't true on all cars. A $200 tune for my BMW 335i increased the HP by 60-70 with only a minor impact. But BWM left a huge amount of power on the table with that engine and it is a twin turbo. My understanding is that porsche already completely optimized the performance of the 996 NA engine so a tune wouldn't gain much.

Yes, he did. Don't know where you got the impression I am looking for free horsepower though.

I think I'll hold off ECU tuning until after exhaust mods

What????? An upgrade is not necessarily a modification "by definition".
For example: Due to issues with some factory F430 exhaust manis I opted to upgrade the headers.

I'd tend to agree if boosted, but I'm talking NA.

The only difference is that $hit goes sideways a little sooner in a boosted car. Either way, you tune out the safety margin and the engine will pop when not everything is as the tune predicts/expects.

I had my 06 cayman tuned there a few years back. The throttle response was better and I did feel greater pull lower in the revs. I had exhaust + headers which responded well to the tune. Plan to tune my 997 as well.

I take all my cars to Eurocharged for everything. Great group of guys.

Sure it is. Actual data and facts are in extremely short supply here, and your argument that your personal experience supports your conclusion is also wrong. That's like saying "I was standing not too far away when the Chernobyl reactor exploded and four years later I was fine, so exposure to radiation doesn't cause any harm." Google "335i tune failure" and have a read.

If you upgrade the headers, you have changed a part of the engine to something other than the original design. Last time I checked, that was the very definition of a modification. And, if said headers provide better gas flow, then a custom tune may be able to get you more power by taking advantage of the better gas flow.

Here's a fact: all other things being equal, an engine producing more power is going to be under more stress and suffer extra wear and tear (strain). Whether any one particular engine or part thereof is already run within an inch of its life (and its longevity is measured in mere hours) or is under-stressed from the factory (and could last several decades) is besides the point. They will both experience increased wear and tear and thus failures as a result of being run harder. The only variable is by how much.

That isn't true and that analogy isn't comparable what so ever. My argument wasn't based on personal experience and I did a lot of research before tuning my car including dozens of posts from people who have run tuned engines for many years. The thread on MHD tuning on e90post.com is currently at 427 pages (and I've read them all). The MHD tuning software (alone) has been downloaded over 10,000 times. The number of N54 engines that have been tuned obviously isn't documented, but the number is high enough to support a large handful of different vendors (ie Dinan, JB4, MHD, Cobb are the biggest ones). I wouldn't be surprised if there were more than 50K n54 engines that were tuned substantially above stock levels. Obviously the volume of n54 engines sold is huge since BMW has been selling that engine in multiple cars for years.
The reports of engine failures are extremely low by car forum standards. The n54 engine has forged internals and has been run reliably well above 500hp. BMW and Dinan both offered full engine warranties on tuned cars.

So back to the original point. Does tuning the car increase wear and decrease the lifetime of the engine in general? Almost certainly. It would be idiotic to claim otherwise. Even if the additional stress didn't, tuning the engine probably also had an impact on the driver's behavior which could accelerate wear.

Is the increase and wear and engine lifetime always significant? Obviously debatable, but on some engines (like the n54) the answer is may be no.