Hallett is one of the great secrets in the US. The track is wonderfully technical. There is plenty of runoff and no walls to hit, other than tire walls, and the folks that run the track, well they are just the best.
If you are interested in running the HST session in two weeks, I would go ahead now and reserve your spot. They generally sell out way in adance. Go to Hallett's website and enter via e-mail or by giving the folks a call.
The track is not bumpy. It is definately rougher than Barber, but it is not bad. In a street car and at speed the bumps will not be noticed. I have raced many different vehicales at Hallett and I've never had a problem with the "bumps". I've even raced my 125 shifter without worrying about the rough spots.
Now in the olden days, there were a few problem areas but they have been dealt with.
Feel free to give me a call with any questions. I'm the head instructor for the HST program.
By the way, Hallett is a perfect track for an Elise or Exige. You don't have overly long straights, so all of the time is made or lost in the corners.