motor mounts are super cheap, its a set of 4 for like 50-60 bucks and mostly easy to replace. 3/4 go pretty quickly anyway

no there aren't any aftermarket headers/downpipes that are technically legal here. there are some you can get away with, but most don't fit right, the o2 bung is in the wrong spot and they hang just as low. i wouldn't bother with those, if you want to change up the exhaust you can get a cat-back system for like $120

just from experience with mine, the resonator (just after the cat) is what scrapes usually on mine, its about under the driver seat. up by the wheels is where the downpipe and cat are, usually those are hanging lower than anything else so that's what scrapes. or it could just be your front bumper. hit the bumps at an angle too, it'll help.

I link to a kit I bought, it worked out well. here there are a bunch of other kits too, with just front end stuff or whatever. Cheap Chinesium stuff but it holds up.