Answer
Well which m5 are you looking at? is it an e34, e39 or an e60 m5? the corvette, is it a c5 or a c6 and is it a z06? these both have to be answered before i could make any predictability here. assuming you have an e36 m5 vs an c5 corvette, the m5 would most likely lose. given into consideration that the m5 does a 0-60 time in roughyl 4.7-9 seconds depending on the drivers skill and ability, now with the weight of lets say 180lbs per person x 5 will give you an extra 900lbs of drag. that alone is a significant loss in acceleration time. the c5 corvette would most likely take the m5.