Back in the HPI Micro RS4 days it was the Graupner 300... now a days its the trinity mass termination motor.. I think.. the one thats part number ends in 95... (19 winds I believe) I haven't run a trinity 17 (17 winds).. On ebay there is a kid from california who sells motors that he mods out.. pro370k or something like that.. they are good runners.. I race gas trucks in the summer and then in the winter we race 18th scale on a tiny 20 x 40 foot track.. it takes a while to scale down to the micros but they are a blast to run... with that hot trinity motor geared down low with atomic gears I can make my car top out at around 35 feet.. It breaks all four tires loose the whole way so it is wayyy squirly.. the track doesn't allow traction compound.. but still, way fun..
