if i was going to buy a bashin buggy it would be the hyper 7
because if your part of the towerhobbies super saver club you can get one for $250 and you just cant beat that price and that would leave you $200 for servos/ upgrades/ spare parts/ or a new engine. tho its fine out of the box for bashing other then the steering servo but thats with any RTR realy
of course the hyper 7 has been around for years and years its a proven tough RC and parts are everywhere

id stay away from the hpi trophy series from what ive read there not the strongest RC's around

now the D8S is the RTR version of the HB-D8 like you said.  its a strong buggy but if your thinking of a engine upgrade right away id buy the kit version.  tho id still go with the hyper 7 if your just going to bash it why spend the extra when the hyper is as strong as any other buggy out there