I'd agree that running costs won't be anywhere near what a AMG, Aston, Porsche would cost and it's still a Golf at the end if the day with all it's benefits.
Pricing will have to be keen but it depends on how many Volkswagen produce.
The lower the number, they higher the price, but then residual values will remain keen. (Think BMW CSL / 1M).
Personally I think they will build either 400 or 4000 units all individually numbered in one spec with no added options, perhaps only in one color too.
The chances of a 5dr will be virtually zero.
You have to look at the special parts that have to be used on this car to see that tooling at the factor will have to be changed slightly.
Bodywork
Alloys
Brakes
Engine
DSG gearbox (stronger?)
Full interior (seats, stitching, mats)
Interior door and glovebox carbon trim
Speedo cluster
Steering wheel and gear knob.
R400 badging
Each one of the above parts would cost more to manufacturer due to smaller volumes.
As a guess i'd say £42,995 OTR will a high spec as standard.
