Didnt somebody on here inquire about this conversion:S
I do 30k miles a year, anyone doing similar in a cup would save 2k a year in fuel, that's enough to pay for a fair few trackdays or a week over at the ring.
So I can see the appeal personally.
That said, I wouldn't expose 172 exhaust valves to that much best probably as they are a little prone to failure even on a standard engine.