The 200-4r and TH400 both require a TH400 crossmember and the 2004r needs a $110 brain box telling it when to lock up the converter. The TH400 requires a different drive shaft length than the ST300, and the 2004r needs a TV cable.

The TH350 is identical except for the downshift cable. No need to change crossmembers or drive shaft length. Rigging up the downshift cable is not that tough.