[Johnny Mullet]

Welcome to the forums! I would find someone with an identical car and try and swap wheels/tires with them for stock and get some smooth or flush wheel covers for them. Don't waste money on Nitrogen, just check your tires at every fillup or at least once a month.

The exhaust could go either way. For my car, opening it up seemed to help, but I keep it quiet with a stock muffler. Maybe if yours is somewhat quiet with what you did, it might be OK.