the viper will also require specially wiring, a computer flash program, custom motor mounts due to location, cutting up the trans tunnel, new cross members, etc etc etc which all come with big $$$$.
Expect this plus headers (???) and all kinds of fab to squeeze that thing in between a firewall and a radiator, in addition to the trans tunnel. I'm not sure the oil pan will clear the K-member either so you'll need to either build/buy a custom pan, or look at the truck pan which is rear sump. I measured once, and I'm pretty sure it will fit in a stock bodied car (not 100% positive though because my radiator was not in the car), but you will have a whole lot of weight bias up front without the engine setback into the firewall. If the 426 Hemi is an elephant, this thing is a whale. It's LOOOOONG, and heavy. Depending on the generation engine, expect 700-750 pounds. Gen 3, 4, and very late Gen 2 motors have cast internals while Gen 1 and early Gen 2 have forged. I would expect, in a stock suspended vehicle, torsion bars are going to be a BIG issue because of headers; that's a lot of tube to work around. I think the stock suspension, upgraded of course, can handle it, but I'm not convinced the car will handle given the weight bias. You'll have at least 2, if not 2.5 cylinders in front of the front axle centerline, plus all the accessories.
Mine isn't a great comparison because I've got mine set WAY back (number 1 cylinder lines up with the front axle center line), custom chassis and everything else. But I've done a fair amount of research on the engine itself, though only a bit about fitting it in a stock bodied car, and even less in a stock suspended car. If you have questions though, I'll do what I can to answer them.