Functional aero, including skid plates, are always what I focus on after wheels, coilovers, and tires. I wait 10K miles before I do anything that can trigger warranty arguments just to make sure the car isn't a lemon. Got Tomei Ti Expreme Type D on my TR, sounds and looks great, quieter than I expected.
For intakes, get Cobb since they have carb stickers. You live in California so you'll need those. They don't make carb compiant downpipes yet, but a Cobb redline, EBCS, and etune isn't that bad.
The rattle on the tomei comes from the springs that attach the 3 exhaust pieces together, you can take em off, I took mine off also there is a vid I watched on YT about it and it won’t loosen your exhaust so you have piece of mind when stepping on it
I got mine from Carmax back in 2021. Yes you can take that Carmax crap off lol. From the inside should be pretty ez just peel it off then use window cleaner. I would also debadge the “Subaru Symmetrical AWD” but that’s just preference. I took mine off just left the “STI” badge on
Try to stick to Cobb everything’s majority of there product have carb stickers and when having everything Cobb it practically nextgen tuned make it compliant in CA. When I had my tomei it the spring that rattle. After a while it will go away or you can pull them off you should be okay. The tomei sounds amazing but after getting the ETS extreme I won’t go back. And they sell intercooler guards that say STI on them.
