I also just ordered a Sparco Harness. I think my car will be pretty bad ass soon (For only having it two months). Heres my mods.
20mm rear sway
Clear Headlight Mod
Custom Mufflerless axleback (2 1/4")
Stromung Midpipe (In a few days)
Sparco Harness (In a Few)
Mobil 1 0w-40
Oh, and of course, (removed www.) RS25.com Stickers