Volk TE37's? Nice choice, I've actually been more of a fan of their LE-37's. Especially in a gold finish. Saw an Evo with them in a magazine a while back. Looked incredibly amazing. Ever since, I've had a wheel crush and wanted a set. Hell, even just to own in my room.
As for the simple bolt-ons, they'll do you some justice. From what I've seen, they'll net you about 16-20 whp. Sounds like you've developed it more for time attack and "canyon driving". Either way, S2k's are pretty hot. If I had my choice of one, I would look into an all white/red leather interior model.
Pity they are discontinueing them. I think 09 is the last year they will be offered. I think the S2000 was offered longer than it was really intended to be by Honda. But still, I've had the pleasure of test driving one. Although, I never had my chance to open it up on the roads, I did get to rev it. It was music to my ears.
Any chance you may sway your opinion on the Mugen top and go out and buy yourself a Spoon version top?