you would have to cut the non-si bumper. The non-si bumper doesn't have cutouts for the exhaust like the si does. The non-si exhaust has a muffler that bends down as it gets towards the rear unlike the SI. Non-si owners who went with an aftermarket exhaust have had to buy the si bumper, or they end up having to physically cut their bumper to get an exhaust in there without it melting the bumper.
Thanks for this, Webby. I wasn’t sure if the Si diffuser hung lower. Wonder if removing the tailpipe finisher would help. Maybe even mandrel bending the tailpipe slightly down behind the muffler. Axle-back swap, too? Just thinking out loud.