Thanks. It sounds like a great experience on the track and a financial black hole off the track. Looking at the price of the cars, it looks like you would spend the equalivant of the purchase price every ten races.You can budget a costly repair every few hours of race.
Usually, this can be more hours before overhaul if you don't drive it at the highest rpm range, or in this case, with full boost. But you might lose some of the fun.
As this is pretty specialized, only the ones who have been supporting this particular type of engine and transmission can give you a clue as to what a repair usually costs. I can advise that a race cosworth V6 costs about 15.000 GBP for a mere overhaul with dyno run without serious internals replacement (pistons / crank). I experienced this after having driven it at over 9.000 RPM. I used to limit it at 8.500 and it lasted for a while, but once, the rev limiter didn't work and I was revving it out of a long corner probably in 2nd or 3rd, and obviously didn't look at the rev counter, when I did, it was too late.
I can put you in touch with some guys in England who support various group c cars and should be able to give you hints on this issue. I'll pm the link.
Driving a sports-prototype is probably the best driving experience you could have (save for a formula car). Our GTs feel like trucks compared to this type of car. Of course, your F50 is not included in the "truck" class...