If you think the 09 diff and so on are not smooth you should see the electric mini inferno with the plastic diff gears. I all so have one of those along with about 20 plus others. I have a lot of race time on my Hyper 8 Pro in the last year with WELL over 9 gallons and if it was not for a brand new Associated servo going bad I would have my Hyper 8.5 Pro ready to break in. I am into racing so much I can hardly afford to eat. LOL[X(]