does it make a big difference in power if the carbs are rejetted?

looks like im getting a 90 gs in 2 weeks and it has this exhaust just curious if the bike is just sounding better or actually will move better:P

thanks

With proper jetting you can get 3 - 5 HP from the pipe. More with pod filters.

Sounds much better (louder) too.

The air dam (belly fairing) doesn't fit with the aftermarket pipes right?

I have a yoshi pipe and a belly pan. I have no issues with it fitting.

As far as the rejet, do it. I was running really lean before I rejetted (previous owner installed the exhaust and didn't rejet)