Holy smokes!! Run from that guy!!!! $17k?
Rear ARB+2 swingouts, around $2800 or so(?)
LRA tank: About $1600 plus shipping
Install of rear bumper is a pain and so is the tank...but nowhere near your guy's price.
Bumper might take the shop the better part of a day.
Tank could be a full day for a guy or more. But unless they charge $400/hour? Man, his math is crazy.
BP-51 install should be well under $1000. Mine was $600 for BP-51 suspension install here in SD after I bought the parts myself.
Full BP setup including LCAs springs, install kits struts, coilers around $4k new for parts only.
My LRA 24 gallon tank cost around $1400 +tax (reduced price for early-adopters at the time, but it's not much more than that now, which I find amazing). But it's not just a tank. It's a perfectly, weirdly shaped tank from Australia, specifically made to fit US spec 200's...shipped from Aus...and comes with double fill spouts to replace your stock unit...electric fuel pump...control button with tank level gauge...and more. Fantastic product, and easily one of my favorite, most useful mods.
I paid VH a little extra for them to steel-plate the bottom against rock strikes. Probably not needed bc it's so well tucked, but they did a beautiful job at Valley Hybrids!! I can't remember install, but it was about a full day and a half in the shop. Maybe faster now? Don't know, as mine was the first one with a Slee rear bumper, and it was just after they first started importing these for 200's. BUT... they charged nowhere even remotely close to what your guy told you!! Your quote guy is either NUTS...or is used to taking advantage of guys shelling out $90k for an SUV.
Call Georg and order a tank. He is here on mud as
@orangefj45 and one heck of a solid dude.
PS. I don't think anyone meant to imply you were cheap.

Many regulars here assume rightly that others are reading along, so general tips often get included, and aren't necessarily pointed just at the person posting Q. So no worries!
Here’s my tank before it went in, showing the side they “up-armored” with incredibly beautiful welds at the shop:
View attachment 1950419