t32

CatStalker: T32 is a great tank, definitely go with the 105mm. If you can play the T29 well, the T32 will just feel slightly better in almost every way, and the gun can be very effective when used smartly.
If the 120mm from the m103 were to be stuck onto it, I feel it would change from a well balanced all around tank to one that would probably be way OP and need a nerf to compensate.