E34 M30 or M50 swap?

[goodfolk]

I have a 1990 525i 5spd manual. I need a motor and I have found two cars that I can get the motor from. One is a 1989 535i(M30)automatic and the other is a 1991 525i(M50) automatic. Which of these is the easier/ better/ cheaper swap to do. I have a tranny from a 1993 325i cabriolet(M20 motor). Will it work w/ one of these motors. Will my drive shaft work?

[nmp411]

The trans from the 325 will not fit anything other than an m20 motor.

As far as ease of swap, the M30 would be easier than the M50.