Originally Posted by Qsilver7

No...it is not as simple as you propose. The reason is...the e53 has a slightly different module communication set-up vs the e38/e39. The e53 has front seat control module set-up like the e46.

The main driver's seat control module (PM-SM) controls most of the functions on the e38/e39...or facilitates routing data to other modules over the P-bus.

The e53's PM-SM does things similarly...but data commands are carried over the K-bus and passed on by way of the GM. You'd have to find a way to bridge/convert this data to get to the correct modules if you swapped in a seat from the e38/e39. Thus crushing your hopes of a simple plug-n-play swap.