hey to all, I have owned a rush for about 6 years now. Ive read all the posts on this thread, and have some info that might help. You should upgrade the chasis to the evo if you have an original rush, it along with the new motor plate makes it alot stiffer. As far as grease in the rear diff, use Tamiya antiwear grease, its super sticky so use sparingly, this also works great to tune the diff. Aluminum arms are okay for show, but once theyre bent theyre bent. Associated spring assortment works excellent on the rush, they have a great rate selection, and are the same length as the stockers. Engines are up to the individual, also depending on what you do, I race mine, so I have to stick with th 12r ss, track rules. As far as spare parts to keep on hand, control arms, spur gear, slipper pads, clutchbells of various teeth count. On the clutch bearing you can replace with ball bearings from Tamiya, I dont know the exact size. Also upgrade the turnbuckles to titanium from lunsford, also available from HPI. I hope this helps. Engine tuning tips, if the tires spin at idle or neutral check your idle speed, if that dosent help check your clutch springs, the stock clutch springs are soft. Hard starts when the engine is hot could be due to the carb setting to lean on the high side. A temp guage will help a lot when it comes time to tune. Tires, for grass I recomend Masher series from Proline or the stock tires from the Cen Mt2 both are aproximately 5" tall, dirt / bashing either dirt hawgs or dirt works, both work for all surface driving. Glad to see that the rush is finally getting some popularity.