The newest tanks henglong has released are lightyears ahead of the old stuff, which has not really been upgraded. The pro versions of their tanks offer metal track, metal wheels with ball bearings, metal suspension arms, IR, airsoft, recoil, adjustable idlers and they shoot at tamiya tanks. The draw back is their apple sucks. If you buy an after market apple from legostore, they then take hits from tamiya perfectly and you are in the game much cheaper than before.
fsttanks has dont many writeups un the newer henglong 6.0 tanks here and on hobbysquak forum.