I think the 90-92 Q45s are the big ones. They changed somewhat after that (I had both side by side at the JY a few years ago, but can't remember exactly what the differences were. The early Q45 halfshafts are 1/8" or so thicker than the 300/s13 R200 halfshafts also. When I was buidling my car, I wasn't sure if I wanted to go 5 lug or 4, so I pulled one setup of each kind since the complete unit with brakes were only $60 each from the JY. The early Q45 is a heavier unit.