Your T3 should've had a long swing axle trany which is the same track width as either the beetle or type 3 IRS width. If it infact has a short axle trany you have some extra fender clearence which you will loose going to IRS . But , I'm just wondering what your going to mount the IRS trailing arms to? Sure , you can switch to IRS sping plates but the swing axle T3 torsion housing does'nt have any mounts for the IRS trailing arms. And the IRS T3 housing does'nt have any frame horns. Soooooo , what have you got up your sleeve to get around this ?