A 4R100 and an E4OD are essentially the same and both require disassemble to exchange the output shafts. The 5R100 Torqshift is just a bolt on deal.
You will have to pull the transmission. $450 should cover the parts in your situation.
I built my own 4x4 conversion for myself and I believe Chris did to (I am not sure) and turned it into a business.
Do your own.
Does being half right count for something? Ah well, it wouldn't be the first time I opened mouth and inserted everything below the hip.
On the parts issue though, and I know this works for the tranny because I did it this way, you can go to the junkyard. I went and bought an E4OD from a 4x4 application that was known to be toast, so I got it for $150. Tail shaft adapter and output shaft for cheap. It IS possible to end up with a bad output shaft (yeah) but not likely. Check your parts and make the right deal with the junker and it shouldn't be a problem.
Anyway, if you're looking to do this on the cheap there is a spot to save some easy money.
DIY to save money is almost never a calculation so easy as just the cost of the parts, or even the labor. Could I make the front spring hangers? Sure. I've got the bulk of the tools in my garage. What I don't have there I have at my business, from 1500 amp welders to a plasma table you could park a 4dr dually on. But that's only part of it.
Do I have the time, or interest in figuring out how to make them? How far forward should the front spring eye be? Should it offset the spring inboard or outboard, and how much? How much drop should there be in the front in relation to the rear spring mount? Do I want to spend the time to source the material, go buy the material, make the part, sand blast the part, take it to a powder coater and have it finished off right? Unless you live someplace like Arizona the rattle can isn't going to last.
For me fabricating is a question of cost, time, and planning. If I know I need a specialty part and it's available I will most likely buy it ahead of time (Chris's parts). Rarely will the cost work out for me to fab it. If I get into a project and then discover I need a specialty part it becomes is it available, how much is it, and how fast do I need/want it? If I need it now and I can fab it relatively simple I'll do it. If I don't need it now I'll buy it.
Someone posted diy4x4 and it's a fine example. Under suspension on page 4 are some nice parts to use. General use tabs (think axle tube shock mounts). Not much more than a triangle with a bolt hole it it. For a pair, $5. I challenge anyone to make those in their garage for $5. If Santa Claus dropped the material on your bench because he read your mind and knew you wanted it you couldn't do it for $5. Not if your time counts for anything at all.
"I can do that myself for cheap", and then spend weeks firing off questions to places like ujoint or baha. Yeah.
I bought Chris's parts because the research was done and I didn't have to do it myself. I could have made them myself sure. And after a handful of trial and error failures and tweaks probably gotten a set that worked just fine. I bought parts from him I could have sourced myself, but I'd have needed to do the research and make the calls. Off the shelf stuff, not fab, but I bought it all from him because again, the research was done, and it was one phone call vs a dozen. Shoot, he gave me (for free) parts to mod my crossmember and when it was said and done I bought a whole new cross member from him anyway because it was a better way to go. And faster ( cut, weld, grind, blast, transport, powder coat, transport, install).
If you don't care about your time and you don't care about figuring it all out on your own then by all means. But if you want somebody else to essentially give you the blue print to their parts so you can make your own, well... If you want to DIY the part then do it, all of it, otherwise buy it from someone that's figured it out for you.
Aimed at no one in particular btw.