the ultras are made by hung nor--and they are lesser quality than the hyper models like the hyper-7, wich is made by bao--both these companys make cars for ofna. just about any buggy made is better than the MTs and such, I am selling a wicked MT RACER (HPI) and I have done extensive reserch on the buggys---
I plan to get the Hyper 7 from ofna--it is a brick house!--the other good ones are mugen (wich, they have their current flagship for 50% off due to a new model coming out!--the mbx) and then there is of course the kyosho=$$$!---the kyosho sport is not recomended. the hyper 7 is a better deal---and is the best bang for the buck. AND if you want to wait a couple of months, the hyper 7 rtr is going to have the hyper 8-port and ball suspension for the same price!---it currently has the 4-port force engine(nothing to right home about)---if you go with the hyper 7 kit, you will get a $100. center torsion diff and a bunch of other extras!
Hyper 7 is what I am doing--they are bullet proof--want more help?--MAXXTRAXX forum has a huge active 1/8 buggy forum that helped me alot.
the ultras are not bad, the hypers are better--they are kyosho and mugen compairable...
Hope this helps,
If you want a 47mph HPI NITRO MT e-mail me