You will have just as much fun in a 'standard' GTI as you would a 2+.
I would even do it in the Touran, be a right laugh
(
I have a couple of annecdotes first:
1. Doing Donington last year just after Inters i saw my brakes get so hot i had no brakes left, so i had to do 3 laps without using them, while doing that i lapped a stock mk 5 GTI
(mine being a stage 3)
2. Doing Knutstorp last saturday a swede who's cupra was at the workshop, took the r888's and fitted them to his chipped but otherwise stock caddy, he had just as much fun as the rest of us.
Back to the subject a trackday meet would allow a lot of people to experience the mods the might have considered, so an excellent idea IMO