Are you starting with a TT01E kit? If so, the drive shaft and bearingsare definite necessities. If the kit already comes with oil shocks, aluminum ones aren't necessary, but RCMart has 3racing ones for the TT01 for cheap. Same goes for bearing steering. And yes, I'd definitely hit RCMart first for the other stuff too; some things (like the steering) are free shipping. I'd also suggest the 58/55 tooth spur gears and larger pinions. The TT01 uses Tamiya's AV size, and can be bought in pairs of 20/21, 22/23, and 24/25 teeth. You may eventually want cvd axles, but be careful there, as some of the aftermarket ones need you to buy different differentials as well. Again, RCMart has some great ones: solid axles, ball differentials, and one-way differentials.