I already have a spare ISUZU 12bolt but it seems to be a bit massive for this and using a limited slip on a trike might make going around a corner kind of dangerous.I've been leaning towards a miata or some other micro car.The part I cant figure out is where does a 6 3/4 come from? Picture this,Yamaha seca 650 front isuzu 12 bolt rear,6 bolt wheels with a set of 32's on.Might be different.