[JWBehrendt]

Well, your picture looks very bad! Metalpieces at the magnets are normal, but the bigger pieces suggest a seiruos damage.
So I assume, your decision to exchange the complete ATX, should be right.
It is possible, to change the ATX without to remove the engine, I did it myself at my X6S1.
Secure the engine by a traverse on top (not necessary to remove the bonnet).
Lift the car (front) to get a clearance of min. 60 cm to ground.
Remove the engine support, as you did to reach the oilpan.
Remove the cross member.
Emptying the ATX oil pan and remove the universal joints (at the differential side).
Secure the differential holes by appropriate round pieces to prevent the differential pinions to fall out of position during the further works!
Remove all cable brackets, connection hoses, the bowdencable for the driving position, electrical connections, etc.. It is not neccessary to remove the starter motor.
Secure the ATX on top preferable with a pulley tackle hosted by the above mentioned traverse to secure the engine.
Remove ALL engine supports. Remove ALL bolts between transmission-bell housing & engine.
On the lower side of the transmission-bell housing you will find a access cover, thru wich you get access to the flywheel bolts.
You need to turn the engine (preferable by using the bolt at the crankshaft belt pulley) to reach all flywheel bolts.
Move the engine to the right side, as far as possible, to get more space at the ATX-side.
Detract the transmission-bell housing from the engine.
Beware of losing the torque-converter!
Lowering the ATX-unit preferable to a rolling-support and take it to your workshop.

To get the replacement mounted, do anything in reverse order.

so long,
John

P.S. If you like, I can give you some pictures from my swap via email.