Manufacture do it for various reasons: reliability, noise level, ease of future power bump, emission, etc. They have to maintain the bulletproof reliability reputation.That is the point, and we wonder why sales are abysmal....
I guess the question would be, how do you leave performance on the table?
Just traction alone, it should be able to handle at least additional 100hp. The launch control is very conservative, the car just doesn't felt like it is stressed at all in any way. Minor mods usually adds stupid amount of power on Turbo cars. M3/M4/M5/M6, McLaren, AMG GT, all respond so well to mods. I was given M6 for Vegas trips for 1 week, the car simply does not have traction, very slow compare to NSX, adding power doesn't help performance in M6's case.