I've done very little to mine. I bought a pre production unit so had to change a couple things right off. I spent $200 and got 3 alloy dif cases and front cvd's (see how much that will cost with just about any other model). I am still running stock shock oils for that matter and it handles great.
do any rtr's have decent servos? they aren't too bad, better than the pre production ones (I couldn't get my tb2 servos to work at all) but the ones in my gt5r I am using one for my front brakes now with the 2 hitecs
I speak my mind openly about stuff, complained about a few small things (mr nutech will attest to that LOL) but all in all it's a very robust buggy. I nose dived mine in clay and dug a 6 inch hole and nothing happened, chassis is still straight. you do need to get cvd's for the front right away and I personally would like to see them as standard. I've spent more time changing the on road car than the buggy
The difs are a cool idea with the spring load, but am considering trying those technokit difs sharkey posted about. fg and nutech difs are same width, and Moo has put fg internals in a case to try out.