Here's what I calculated in the first post of the gauging interest thread:
Your costs are very conservative I'd say.ferry/tunnel - £100
Fuel - £150 (600 mile return trip between Calais and Nurburgring, using 25MPG and £1.35/litre) doesn't include fuel cost of going round the 'Ring or getting from your house to Dover. If we cruise the motorways, which I'd suggest is probably a good idea, no reason we shouldn't see 30+ MPG.
Europe required items - £50 if you don't already have them (now require breathalyzer for France of which we spend about half an hour in!)
It is best to book as soon as possible, but until the date is 100% confirmed there's no point! Especially with now finding out about the festival, it may well be moved.