modern engine swap 73 charger

[AmadeusCharger500]

I'm sure this topic has been covered but I cant seem to find it.
If anyone has a source for these questions and options for putting a new chrysler product engine into a 70's mopar.

Body modifcations?

Maintenance? (can you change the oil without lifting the engine.)

Complete costs involved? from engine to trans to computers and wiring.

This is a good article but has no indication of costs, (i'm positive someone has that info)
http://www.hotrod.com/how-to/engine/ccrp-0905-hemi-engine-swap-guide/
Also the article only talks about 5.7 and 6.1 hemi. Are these the most common choices?