It’s always better to not upgrade your car too much beyond what the factory allows you to customize at the point of purchase. One (painful) decision Porsche has made is to actually not allow anyone to customize the sound of the exhaust system, it sounds as it sounds.
Important to note that some 911s such as the GTS, GT3, and of course the GT3 RS do come with a button that if you click on it – there is more sound.
As for the rest of the 911s, even the Turbo S (which is the fastest of them all) come with a more modest exhaust sound, at least if compared to the likes of Lamborghini, Ferrari or McLaren that are equipped with more aggressive (but beautiful) sound.
Robert LeBron from Manhattan Motor Cars was kind to show us the 911 Turbo S 2015 sound, just in case you’re wondering.
GT3 RS
Lamborghini Huracan