I was in your shoes a few months ago, i bought a TG10 second hand it sucked arse.... that car made me loose interest in nitro all together...
My mate has a V-ONE-R which is as stock as they come and i was quite impressed watching it tear up the track last weekend, the car handle superbly and ran trouble free all day..
If i ever decide to buy another nitro it will be a Vone series car, unless i can afford a MTX 3 LOL
Regarding engines, my mates car had a $100 engine ( his words) and he qaulifies in the a main againts novarossi's and the like. and it looked super fast on the track...