I would vote backdate (because I'm interested in doing that too)

Find a decent (but good running) SC - $12k
"Bolt on" body mods/paint - $5k
Misc improvements - $3k

Ta da!

...does it HAVE to look exactly like an RS? I like the idea of an "RS spirited" car, but not an exact replica.

Doug-

I like the cost numbers you're using! It won't be an "exact" replica, but will hopefully capture the spirit of the 73 RS. It needs to be fun at the track or on the street.

I haven't ever driven one of these "clones", so I'm hoping the performance is as good as people make it out to be. (Or at least as good as the car looks!)

Sounds awesome. Be sure to post progress when you get to it!

The 80s cars are pretty awesome...and backdating will get rid of heavy bumpers and other misc 'weighty' items. You won't need to updgrade to a lot of power if you're taking off a lot of weight. That's the beauty (the "spirit" if you will) of the RS.

Good luck!

Somebody just posted a car like that in the "For Sale" section. 73 RS Replica with 3.0 engine. $20000.

This is the car I was considering for the project:

http://cgi.earthlink.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=10156&item=4525291 501&rd=1

Unfortunately, the owner never responded to my request to see it...

Not bad for the price! But I still think you're better off finding a good running newer car and just doing the cosmetics. But that's just my opinion!