For people who have had both, which is louder?

 

991 I would say. 997 might seem louder from inside but that's because overall the car let's in more noise (or so I feel). The 991 has more to its sound range too with more burbles and pops.

 

991 PSE has a lot more crackle and pop than my 997 did.

I find 997.1 PSE sounds way better than 997.2 (the first gen DFI engines didn't sound that great and weren't that loud)

But the 991.1 PSE is bang on, and at least for me the best PSE they've released to date