i went on one a few months back, and was a brilliant day aswell, drove a rally prepped evo which was fairly quick no lag at all, drove a fairly new scoob STI which was a great car (not as quick as the R in a straight line) with fantastic handling as standard, a rally polo 16v and a rally pug 205 gti.
heres a web address of the company who do it fairly cheap aswell,
http://www.ferraridriving.com/rally.htm
here are a couple of pics when i did mine
this isnt me driving but this is the scoob i drove
the only thing, you get there you think you know how to drive, coz you have a powerful motor, but you know foook all, these are guys in there 50's and still hold there wrc license and know there stuff.