Okay so I drive a 2004 G35 coupe auto (sadly lol) and I recently purchased a mid Y-pipe to install. The only problem is the nuts and bolts on the gasket are rusted and won’t even loosen up after adding wd 40. Is there any methods or tips that might work as well? Thank you..

 

Kroll oil, Pb blaster, torch, hand saw and oh prayer.

 

Yep. WD-40 is pretty useless.

The bolts on mine were so bad I couldn't even get the socket to grip. I had to cut them off with an angle grinder. The Y to cat connections use studs though and not bolts, so you'll have to pop out the remnants of the studs and attach the new pipe with bolts. I suppose one could press in new studs if so inclined.