I effect, both of my superdukes have been track bikes, 'cos I seldom ride on the road.
My current one cost £5250 - 11 months old and 700 miles on the clock. I got a great deal on the akros - fitted them myself and then had the bike mapped for nowt by my (first class) dealer.
If you intend doing trackdays - you don't need a bellypan. I have raced with rhiem racing and swiss moto in europe, neither required the pan to be fitted.
I guess what you will get with a ex-cup bike is a tuned motor. I'm not sure what HM racing do, I think it's head work and a more aggressive cam.
TBH - had my 05 bike been stolen, I had intended to have the motor done this winter. I have since had second thoughts, because while that additional (I'm guessing here) 10 - 15 BHP will be great on the straights, it may detract from, what in my opinion makes the superduke such a great track tool - it's tractability out of corners.
BTW - over the last couple of days I've had some coaching from Simon Crafar (EX factory WSB rider and 500CC GP WINNER). Over lunch he mentioned that he'd had a go on a superduke around donnington, and he really rated it!