Redbook is total crap man, you can't take their word for it because they assume everybody has driven the car equally (average 14,000+ KM/year, wear and tear etc) when in fact a lot of ITR owners are very enthusiastic about maintenance etc.
I'd be surprised if I saw a DC2R even in average/decent condition go for less than $13,000. Demand is still ripe for such a classic car and IMO they'll go up in value once they drop in numbers a bit more/after hitting 'classic' status.