Donor Lesabre-2003 Limited, recipient Lesabre, 2004-Custom. How much of headache to install the following components from the Limited to the Custom, stereo, HomeLink, Dual Zone Automatic HVAC controller, headlights (with cornering lamps). By the way, I removed the the front end wire harness (GM part #5023) from the Limited with easy. Anyone know if I need to do anything before I swap out the Custom (GM part # 5022) wire harness for the Limited? I hate to short something out.

The DIM, IPM and stereo are all VIN matched. The radio will display 'LOCKED' in an any ignition position other than Accessory, after the ignition is turned on the first time (until the battery is disconnected), unless matched with a GM Tech II programmer (or the newer programmer). I would expect there is a fan controller module that would need to go with the HVAC control head as well. There a numerous thermocouples used in the dash of the automatic climate control system that may not be present without out it.

I've only touched on the differences of which I am aware. Sounds very challenging.