That Jay Kay car has been on the market for some time, at least a year and probably closer to two. I remember seeing it some time ago. Given that it hasn't sold and I'm sure Jay Kay has the money to maintain it property I would say the market for high value E30 M3's is quite small, unless one of the special editions maybe. The Jay Kay car has probably be maintained with no expense spared.
They are fantastic cars. Aging now yes, slow in a straight line compared to new cars but it's all about the complete package. When the E46 M3 came out I remember the E30's giving them a run for their money at track events (providing straight not too long ). But, at the lower end of the market there will be a lot of rubbish about. They do rust too, and the rust can be well hidden (outer panels look good, bulkhead can be rotten for example).
I've had a few in my time and thoroughly enjoyed them. One was bought with just 38k miles on it and one previous owner. 2nd was a rare UK spec Evo 2, which later went through restoration (rust!).
As they are old cars now, and quite expensive I would only buy one that has been completely restored and there are a few about now, or look for imports from warmer climates that have been used as summer cars only and definately get fully inspected by a specialist- there might some expensive hidden nasties. A lower risk alternative could be a 320iS. Made for the Italian and Portugese markets only with the same S14 engine but smaller displacement (2litre) but apparently is a very sweet engine. It has the std E30 body however. But if imported recently shouldnt have the rust issues.
