If you look at extreme setups such as a drag car which is running thousands of HP, they need to be pulled down after each 5sec run, my mates dad has a 5sec drag car and he tells me the stories which is just mind boggling so u need to be rich with sponsorships.
Yeah I've heard it from a few guys actually but wasn't sure how true it was as to me, pulling it down every 5000km would be painful. 20000km on the other hand wouldn't be sooo bad for car which isn't a daily driver.
I was interested in buying Envy motorsports 'the jetters edge' r34gtr a while ago and he killed the sale when he told me it had its routine 5000km rebuild.