Actually the swap to the two speed is extremely easy! Probably the hardest part is getting the stock clutchbell off which is quite simple. However it is kind of a pain to adjust the shift point while running because you have to line up the hole in the spur gear cover with the correct hole in the transmission which can sometimes be agrivating. But very important! make sure to use threadlock on the set screw that holds the shaft in place, not the adjusting screw of course, because it WILL come out and it will not shift which caused me to hunt endlessly for other problems because it is hard to see that the screw is missing. And don't doubt HPI's advise to use it for street only, I didn't have problems with durability as they say you will, but the performance in tall grass or the most minor of non-track off-roading is truly depressing considering it is a 4wd truck. Which I guess could lead to durability problems but when I had it on there, there were no such problems for me.