My only regret was leaving my car to an incompetent mechanic (mostly dad's fault lol)
V6 would be nice but for the hassle it just isn't worth it. If I had a Gen 2 turbo chassis then I may have leaned towards V6 only because it is a better base to build on: gearbox, axle etc
I'm quite happy with the stock motor, it does lack a bit of power but makes up in the handling and driving feel department. Upgrade wise a better exhaust system, custom cold air intake using K&N Apollo would've been dainty. I have koni yellows with RSR Race springs which improved body roll and rebound but the spring rates are still on the soft side (to me) and bump adjustment would've been useful
My next upgrade will be a new car but that's a secret ;)