VSR or CoupeKing (they the same as LaJolla?) probably would charge $200k for a #1 show car. Bennyz proved they can do good work and for fair amount of money. Paint/body work...doesn't really matter what kind of car it is; if they've done show cars before, they can handle a steel body E9.
Assembly/re-assembly of an E9...looks like they can do it. All other stuff can be outsourced, akin to what Scott went through (interior, wood work, motor).
$200k: depends on the starting point, right?
Where Benny and his shop seemed to struggled a bit (and needed the help from this forum) was with modifications and mechanical stuff.
If this is a strip, repair rusty metal, repaint and reassemble back to the way it came in then the only bumps in the road (from Scott's amazing experience) will likely be
(1) Shop leaves it to the owner to find body styling line and paint flaws. The impression I got from Scotts posts is the shop waited for Scott to point out flaws in his paint job, and for Scott to have to ask for this stuff to get fixed. That might not be right because I wasn't really there to know what really happened. That's just my take from the thread on the work. And ... the reason you go to an experienced pro shop is so you DON'T have to monitor the quality of their work and so you CAN rely on THEIR expertise to do things right and fix things that are wrong. The average Joe may or may not have a great eye for paint quality and a good shop will enable you to sleep well knowing
the shop manager and project lead are using their 100x greater experience to look out for your interests. I didn't get the feeling that was always the case for Scott. Imagine what might have happened had Scott not pointed out the quarter panel style line or the paint issues . . . This is why people go to places like Paul Russell. Paul's shop sweats all the details for you. All you need to do is pick up a pen and sign checks.
(2) This shop may struggle just a little bit to replace parts that can't be cleaned up (like tail lights, some rubber) or when reproduction parts aren't readily available. Shops like CK, VSR, etc have great access to NOS, used parts via their client base.