Nope doesn't make a difference. Please verify the motor is a 99-00. Those ****ers up there in Canada(cough where I got my motor from cough) lie and say that shit. Then they send you a ****in god damn 96. Trust me!! I can't stress that enough... anyhow.. your cat will mount to the header but... the B pipe is like and inch or two longer so you exhasut will stick out a tiny bit further(doesn't look bad at all) and the bolts will kinda go in throught the holes at an angle. AS you tighten them they will straighten up, but you will still notice they are crooked when its all tight. But you shouldn't have any exhaust leaks.