D8 all the way! i used to not be a fan of the HB at all then i bought one to try and man im glad i did! they are awesome and handle better than anything i have driven, i like it better than Mugen and alot better over losi IMO. i think mugen and HB are very close but the HB is a little easier to drive and im way consistent with the HB. my fastest lap is about a second faster than my average, and i have only race the HB once. i ran a others and my fastest lap was over 2-3 seconds faster than my average. also my laptimes have gone down over a second. my old fastest laps are now my average lap. and the build is really easy minus the shocks, they were the only thing that gave me problems. also the one piece engine mount might need to be grinded down a little in the front depending on the engine, i know picco based engines will need alot a grinding.