Not sure how old this is now but for what it's worth... This is interesting because I sold two similar cars on this very forum! So I thought I'd relate my experiences.
The red car went for the asking (5k). In fact the buyer was so keen he was prepared to pay more. How much more? I'll never know. But it was a good honest car just not matching numbers. The buyer will have done well. It was a nice, straight unmolested car.
The white one was rougher. Asking was 4.5k but it went for 3.5k. Condition wise I'd put it on par with David's car (with all due respect I can only go by the photos provided). Again not a matching numbers car though. Would this have made a difference? Probably a bit. Would it have doubled the amount I could have asked for? I suspect not.
Fast forward a couple of years? I wouldn't put that much more on them. I suspect JSA's suggestion to export via eBay UK may have netted more money for my other projects but that's life!
The ones that sold on eBay for 18k? Freak occurrences that demonstrate what a niche market we are trying to sell into. How many buyers at any one time? Sure one buyer will pay 18k. Another will only pay 8k (assuming cars are similar). It's the size of the market here guys. Tiny. Try buying a mint one. See how many you can find for sale. People are hanging onto the really nice ones.
Nothing wrong with the brand. Sure it's not GTHO or GTS but it's remarkably well represented across the racing and restoration spectrum. It's the size of the market.
Without wanting to sound nasty, I think the cars we see for sale are the ones that aren't viable as a wealth storage vehicle. They require either a lot of work or are suited to parts/wrecking (which I see is popular). These cars fought hard to be desirable but ultimately weren't as desirable as others. Witness the preferance for the flat nose models and the trends to convert RS2000's into flat fronts in the UK. Actually hurts to say that because I love them. And that right there is the signature of passion trumping concerns over values.
As a side note, I recently sold a 4 door RS2000. Quite rusty in all the usual places but salvageable (and indeed the buyer is restoring). It was a rare auto optioned car. Great interior. No engine or 'box. $750.
Blame Ford. It was their great idea to option a 2.0L with RS bits in the greatest dumping ground in the world. Australia. It wasn't even offered with any power up options under the bonnet. Like IDF Webbers and cam. We should have got the Euro version. Just imagine.
Food for thought. My 2 cents.
I'd be interested to know how this went and I wish David all the best in the sale. I kind of wish I'd considered eBay! Might have jagged THAT sale by THAT buyer as mentioned by Neville.
Dan that red one would fetch an easy 12K these days. In regards to what you mentioned about the market- Vehicles get a LOT more exposure on Ebay. Buyers know & trust the website and feel more comfortable placing the big bids. I tried to sell a MK2 RS2000 instrument cluster a few weeks ago on a local Escort facebook page for $250 with no interest. Put it on Ebay and it sold for $480 incl postage!