It's easy, but requires some math skills, labor, access to parts or cash to drop it off and pick it up done.
I've seen people drop the rear end assemblies out of LX cars (Charger, Magnum etc), modify the mounts on their LH car chassis (not an enormous difference, but enough of one), drop the LH fuel tank, shift the exhaust and rock and roll.
Trouble is using your 2.7/3.2/3.5 motor, the LX Mercedes transmission (Some Audi Tranny's apparently match up too) and getting it all to work.
Your best bet would be find a wrote off LX car at the yard, yank all the electronics and wiring and bolt up the transmission, fit the rear end and you're 100% good. Mind you there is A LOT of stuff in between what I just said. lol