RPM A-Arms, Traxxas Auminum Caster Blocks, Traxxas Aluminum Axle Carriers, RPM Bumpers, MIP CVD's or Tekno Dogbones, Sway Bars, Proline Powerstrokes or Traxxas Big Bores, New Tires (reccomend Proline Trenchers), Motor Heatsink, King Headz Aluminum Motor Mount, and a new body eventually. I converted my Slash 4x4 to a Backslash 4x4 (there is a thread if you are curious) and I have some of these parts. I have RPM A-Arms, MIP CVD's, Powerstrokes, sway bars, and an integy motor Heatsink. The other upgrades I mentioned are what my friend has. If you have any questions just ask!