Hmm. Can someone just critique my example here? I haven't used vehicles much in SR4.
HMG FA narrow against Hotspur (Bod 18, Armor 10):
7P/-3, (let's say 2 net hits), so that's 9P/-3 for armor (Physical and penetrates armor), and a total of 18P versus (28-3)=25 Resistance, right?
So, in standard rules that's 18P - (let's say 8 resisted?)= 10 boxes (crap), and each passenger takes 18P and resists with Reaction (-2), and then say, 4 Body + 8 armor + 10 vehicle armor (say, 7 resisted) = 11 boxes. So, everyone's dead and the truck's half-mangled (10/17 boxes), for 10 bullets?
In Draco18s's method, it'd be 12 boxes against the truck, and (12-3)=9 boxes against the passengers? Maybe I should use a lighter MG.

Perhaps if a 'full-auto' attack works on vehicle *and* all passengers, it should be at least a nice 20-round suppression instead.