Talk to Charles @ Powertrix about his Fiberglass rear hatch. It's much lighter than stock when I felt it. Also talk to him about Carbon Fiber or Fiber Glass T-Tops. Additionally I remember Harry (Ztuner) have very wide tires (front & back) on a track car. Mike Kojima posted a long time a go about his "track" 300zx TT in progress, search for his posts for some more great ideas. Sorry I can't recall his SN, but I think it's smartbomb or something like that.