Ebay's usually a good indicator of market value. If it's too high you can always come down in price or negotiate with someone's lower offer. This is probably one of the best places to sell it given the concentration of enthusiasts with our bikes. You might be able to check posts back a ways and see what guys were asking for seats and risers on here.

2005 Speedmaster, Tornado Red, AI removed, Uni Pods, JCW 19" turnouts