I do loads of trackdays (check out
www.trackfun.co.uk for dates), plus do endurance racing (in Clio's -
www.teamthink.co.uk) and race/trackday car preparation (Clio's, M3's, Fiestas, etc) - so happy to help.
I've just acquired a Mk2 16V that I am building into a track day car - havn't got very far yet though...
As previously suggested, get a rollcage - Safety Devices do them 'off the shelf' for most cars. They are fairly easy to fit, but you need to make sure that you reinforce the mounting points with welded-in plates as you don't want the cage parting company with the body in a shunt. Plates should be at least 20mm bigger than the 'feet' on the cage and should be 3-4 mm steel. Any engineering shop will make them for a few bucks.
It is worth fitting a proper 'race spec' electrical cut-out switch - these cut the supply at the battery which is of benefit in preventing a fire if you have stacked it!
Change the brake fluid for DOT4 (AP Racing do a race fluid called 550, I think, which is good) other wise you'll boil std stuff and get brake fade very quickly. You might be better running some brembo or similar grooved discs as std ones will cause your pads to glaze and be less effective and will probably warp.
If you're serious, get a proper race spec suspension kit. Contact somebody who races in the VW Cup and I'm sure they would suggest a decent set up for trackdays.
It's worth changing the suspension bushes either for upgraded Powerflex type or new VAG ones as this will make the car work better.
If you can afford to change the tyres, get some Yokohama 032's (sometimes known as Yokohama ADVANS). They are a road legal semi-slick and are great for trackdays, they're so grippy!
Let me know if you want a seat and harness or any other new bits as my racing buddy runs a race parts supply business and can get good deals.
Regarding insurance; most people on trackdays don't bother. If you throw it off the circuit then you'll have to pay your own repair bill. If you shunt somebody else (or they shunt you) then it is down to the two drivers to pay for their own damage, one of those things, but they can't 'claim' against you. Insurance companies charge silly money for trackday cover and have huge excesses which make it unrealistic.
Hope this helps.
Cheers,
Martin.
