I think what Pete was saying he thinks is boring is your repeated communications about low valuation of a standard car, I don't think he was referring to the value comparison between an Evo and a regular car... Pete correct me if I am wrong.
Actually I think you may have touched a good point about the difference in value between Evo, ex-Works car and Standard cars, and I think maybe you are wrong in believing that an Evo should be worth twice as much... The sales volume of these cars is so low that it makes it hard to make a pattern and a recently it seems that all has been based around the recent Evo sale at Coys which of course as already said, one car does not make a market.
Another thing I don't understand and have never agreed to is the reason why rallycross Evo's should be worth more. Of course if they have a history of victories this will call for some higher cash but in most cases these cars are fully stripped down RS200's rebuilt for racing, battered up, crashed, straightened and then reassembled back into road cars after their racing career ended. To me (just a personal opinion) a car like this would have no value added whatsoever... Being able to say "I have XXX Rallycross car in my garage" means nothing once the car has been reassembled into a road car and no longer looks anything like it used to when racing. Not to mention that many rallycross cars were bitsa cars and others were standard cars with BDT-E engines in them (which in my opinion does not make them an Evo).
Lastly, IMHO, the real valuable RS200's are the ex-works (rally) cars... They are the easiest to trace and they have the history that goes with them. Incidentally, except for the Marlboro livery car, none of these are Evos'.

. Tentenths, since you are looking for a car to race I think you should be looking at one of these and be prepared to spend 150K upwards for a good one... Buying a standard car for say 70-80 K and converting it for proper rallying will probably end up costing that much anyway or if you're lucky only slightly less. The same will apply if you buy an Evo... Don't think it will be ready to race, let alone being eligible... If scrutineered correctly at a historical event, an Evo may not be eligible, since it was never raced in 1986
My 2 cent.