The F-car front suspension (same as M- and J-body--plenty of Diplomats & Fifth Avenues around) is fully self-contained: Torsion bars, sway bar, steering, brakes, everything is mounted to the K-member. All you need to do is fabricate a couple of mounts for the K, and you're done. It's a weekend job, really, most of which would be spent getting the K mounted straight. You'll need to do some welding, obviously.
Very little has to be done to the trans tunnel--most of it at the front, to clear the bellhousing. The cars already have a driveshaft hump, so to speak. The fuel tank needs to be moved, too.
The unibody doesn't need to be strengthened, in fact the FWD cars are generally stiffer and stronger than the cars with which we're familiar... being more compact, they're inherently more resistant to twist.
The rear frame rails of the K- and L-based FWDers will be real familiar territory to fans of muscle-era Mopars, and hanging a rear suspension isn't particularly traumatic.
Still, if this is your first engine-swap deal, a FWD conversion may be a bit more than you want to tackle first time out.
