What 71-73 Cougars would you consider worth saving if rusty?

Just in case there is a sufficient number of people that don’t frequent both sites I’ll ask this question here too.

There are a lot of very clean 71-73 cougars out there for very reasonable prices. What cars, if you found a rusty example, would you consider worth the effort to save?

An example I am thinking of is the only white 429 ram air, 4-speed '71 convertible that sold on eBay this past February (http://www.ebay.com/itm/Mercury-Cougar-standard-1971-mercury-cougar-429-cj-4-spd-r-a-convertible-1-of-1-/321654868317?forcerrptr=true&hash=item4ae41fc95d&item=321654868317&pt=US_Cars_Trucks&rmvSB=true)
and discussed on ‘the other site’ here
(http://www.mercurycougar.net/forums/showthread.php?89554-71-Cougar-Convertible-429CJ-Ram-Air-4-speed).
It’s very rusty, but wouldn’t it be worth the effort to save this car especially considering a solid donor car (driver quality in its own right) could be had in the $10k range. What other cars would you guys consider worth saving?
429 ram air or not? other?
Auto or 4-speed?
XR7 or Standard?
Convertible only or coupes too?

Of course the follow up question is ‘Why?’ ‘Worth’ can be financial, historical, personal or other reasons that give that car enough value to make the effort to save that particular car. I want to avoid ‘personal’ reasons (for example, your step-mom’s 351-2v std that was the first car she bought new) as I have no personal connection to any cars in my past. I want the car’s merits to stand on their own, without personal experience affecting judgement.

A lot of variables to consider. Among them: willingness to take on a huge expensive project, time and space needed, available funds, etc.

The older I get, the more wisdom I gain. “If it is worth doing, it is worth over doing.” is one of the lines in a signature of a recognized auto restorer. Quality work, takes time and talent. A high end, or rare car, deserves a concours restoration. Anything less, greatly diminishes your investment potential, and the potential value of the vehicle to future buyers.

I know you expected us to say “any 1971 429 Cobra Jet” and I will say any 1971 429 Cobra Jet should be saved, up to a point. Chasing down dated 1971 429CJ engine parts is tough and expensive. Lots of other general Cougar parts such as grille pieces, lenses, door panels, etc, are explained in our recent video. https://www.youtube.com/watch?v=WCNOiNCZVtU&list=UUYa8RloDs5J8xltL9ZMMB-A&index=1
I am sure that my answer 15 years ago would have been different.