But what
is that surcharge?
It is a cool car, but will someone drop $15, 20k, 30k on it? It may be a very non-linear curve, price vs. condition. And it can go either way (flattening out at a certain price, regardless of condition, or going through the roof when approaching perfect condition, like that MB you posted on the SL500 thread).
One though I had was if the turbo kit helps or hurts this car's value. Are there purists that want an all stock car? Would it be better to return it to stock and sell the turbo separately? It sure looks like it could be worth a couple grand by itself.
To get a good market value, I would look for pristine examples sold on Ebay. Do some digging in Deutschland too - here an example:
http://suchen.mobile.de/auto-inserat/vw-scirocco-gt-1-hand-orig-36tkm-sch%C3%B6neck/174235036.html?lang=de&utm_source=DirectMail&utm_medium=textlink&utm_campaign=Recommend_DES
European prices are usually a good indicator. That car on mobile.de is as pristine as it gets for Germany and dealer price is 14k Euro. That's $20k, but it is at a dealer and already in the Fatherland. To make an import worth someone's while, a comparable price may be $15k?
So, looks like $15k would be doable. There are more examples on mobile.de but the one I found was the closest to my basic knowledge about these cars.
I do however know that
I would never spend $15k on any Mk1 VW ...
G