Do I need new gaskets or fasteners to install this?

Basic hardware for clamp connections is standard, but OEM gaskets at the connection point are recommended for a clean seal. Grab fresh gaskets when you order — they're cheap insurance against leaks.

Will this fit if I have a cat-back system already installed?

This is an axleback, meaning it bolts directly to your factory axle and replaces only the rear muffler and tips. If your mid-pipe or catalytic converter has been modified, test-fit before committing to installation.

What kind of sound difference will I notice?

Expect a deeper, more resonant tone compared to stock. Since you're keeping the factory converters and mid-pipe, it won't be raw — it'll be a refined upgrade with a noticeable presence at idle and cruising.