You are still welcome here. Our cars share a lot with the Celica GTS, particularly from the firewall back so we need to work together as much as we can.
Whether Supra or Celica, I suggest just buy one that's already in excellent condition. 1) There's almost no reproduction parts to make it look like new again. We can get most of what we need to keep them running, driving and stopping because of the shared parts with other Toyotas and even other brands and models of car, but there's almost nothing reproduced that's specifically for the Celica or Supra only. And unlike earlier classic cars, many parts were originally made by complex machinery and can't be easily refinished by hand. They're for all intent and practical purposes, unrestorable. 2) With the costs of professional services that aren't easily DIY that you would traditionaly have to pay for during a restoration like a proper paint job, upholstery and engine machine work soaring after the pandemic, paying $20K+ for an excellent example on Bring-a-Trailer is even a greater bargain than ever. All those typical restoration tasks cost the same whether you are restoring an 85 Celica or a 67 Shelby Mustang (only the parts prices for the Shelby are likely cheaper since they're all reproduced in China). But the Celica isn't worth much more than the cost of a proper restoration paint job while the Shelby is worth ten times as much. In short, just find an excellent example and skip the idea of restoring one. If you are dead set on a retirement "project", try to find one that's already beautiful cosmetically inside and out and only needs a mechanical refresh.