I have a slight rattle at around 5-6K RPM. Should I change out gaskets?

Are the cats the only mod you have done to your car? I don't think gaskets are the problem. Exhaust gasket leaks make a ticking sound that you would be able to hear the entire time the engine is running, not just at a certain rpm. Have you checked to make sure all of your bolts are tight enough?

I have a Stillen Exhaust & G3 Intake also.

Yes I have checked my bolts. I will check again on Tuesday

Is the rattle sound like its metal hitting against metal? The earlier version Stillen exhausts had some clearance problems with one of the factory chassis braces.

Berks cbe doesn't have this problem right?

No it doesn't. I think Stillen has fixed their exhaust as well so they don't have that problem anymore either. Just depends on when you ordered yours.

Ill find out. I will try to insulate the contact points tommorow

On a semi-related note, can anyone tell me if the 350 and 370 use the same cats? I have a pair of test pipes from my 350 that I'd love to bolt up, but I wasn't sure if the dimensions were the same.

i think the 07/08 cats are the same

Yeah its the same cats as the '07-'08 350Z with the HR motor. '03-'06 350Zs don't translate.

Ok. Mine was an '05 with the DE motor, so that's not gonna work. Thanks for the clarification.

just buy a new set from one of our vendors :tup:
you'll be happy you did

In light of this new information, I think a full exhaust is a given. I got to see the underside of my car the other day and nearly sagged my knickers when I saw how tiny our piping was.

you didnt have to unhook the steering knuckle on the drivers side?

Nope