If I change out the 4 speed in my 78 733i to a 5 speed, is there anything that is going to bite me? Is the 5 speed box longer in length so I will need the 5 speed driveshaft? Also, I still need to buy a hub that goes on the front of the crankshaft of this car (balancer bolts to the hub) - mine cracked, does anyone have one laying around? Thanks!