At that particular event there were:

3 Mustangs (2 with cages)
1 3rd gen RX-7 - Fast in a straight line
1 1st gen RX-7 - SCCA ITA race car
1 C4 Corvette
1 65 Corvette - Trailered in race car
1 Mini Cooper S
1 C4 Gran Sport
4 C4 Z06's
3 Porsche 944's
1 Integra
1 Sentra SE-R
1 95 Eclipse AWD - former One Lap of America car

As you can see there were only a few FWD cars there, but that varies at every event. Usually there are a lot more cars period. A regular DE at a bigger track like Mid-Ohio or Putnam Park will attract 100+ cars. Hell my first instructor drove a Cavalier rental car with 2 year old hoosiers on it - and he was faster than me. If you're thinking about doing one, I would highly recommend it. It is by far the best mod you can do - making yourself a better driver. Don't worry about the FWD thing, it won't make a bit of difference.