I have owned the Losi Mini 8ight-T since it was released. Make sure you read the manual and break in the differentials. Its a love hate relationship with this car, when it is working its amazing to play with, its really dialed in, just like an 8th scale Truggy. But its weakest points are the differentials, absolutely garbage. Even though I shimmed my differentials from the get go, I managed to ruin 4 of them and they aren't cheap to replace. We hardly jump our Truggy and still managed to chip teeth on the differentials. I was told by Horizon Hobby that the V2 version of the differentials is supposed to use better material but I am still waiting for my order of V2 differentials to arrive.
Other than that, I have had issues with the ball ends coming loose from the knuckles, hubs and carriers. I have no idea why because those are plastic but I went ahead and upgraded those parts to GPM aluminum parts and used thread lock, no more issues after that. The stock shocks are great, depending on how high you plan jumping the Truggy you might consider getting some stiffer springs and changing the oil. Of course like others have mentioned, if you want to get the most out of this chassis you will have to upgrade the motor. I replaced the stock motor with a Velineon because it was a direct drop in. The stock motor over heated with a 2s battery while driving on artificial turf therefore I had to replace it. The Velineon does get hot when bashing in thick grass otherwise it does fine if geared correctly.
Make sure you cover the gaps in the spur gear cover, although it seems like its a good fit there is a little gap and pebbles/dirt will get in and break the teeth of your plastic spur gear. The stock tires work well but will wear out quickly so you might want to source some new ones with a 12mm hex with the appropriate offset. You might want to upgrade the front hinge pin holders to aluminum, I damaged mine by nicking the wall while exiting a corner, I didn't think it was that big of an impact and at slow speed as well, but the plastic brace did not last.
That is all I can think of right now.
ZK