Right now I am ripping my Seville STS 2003 apart in trying to find a elusive misfire but upon putting it back together hopefully issue solved, I’m gonna be deleting the cat and installing a 3” pipe back to some muffler brand not sure yet. I’m gonna do my best to follow the stock exhaust path keeping it as oem fit as possible. I’ll be using T304 stainless vibrant performance mandrel bent tubing and probably a few flex connectors. I’m sorry I just don’t believe that this exhaust is perfect for this engine no matter what GM or experts say. I’m building a 2.4 K24 Honda and they thrive on 3 inch exhaust and anything less and you’re leaving HP on the table. That’s a 4 banger so no way a 4.6 is breathing its best on this tiny exhaust that tapers down to less than 2 inches lol. Intake wise the stock intake should be perfect it’s got a big throttle body for stock as well as tubing so I’m gonna leave that. But as far as exhaust it could use a bigger diameter. It’s too bad no one makes headers for these cars this thing would sound insane. Any tips for DIY stuff I can do with the harness and radiator etc ripped out? I’ll have the injectors and such out as well along with the intake manifold.