Get ready to see a lot of pretty wild stuff at Nationals. I know of two guys from my area (Central Carolina & South Carolina region) that will be making the trip for DSP. One has a SRT-4 with 285's on the front and 245's on the rear. Another drives a '99 Impreza with some pretty wide tires that offset at least 4-6" outside the fender well. The Impreza will probably compete for a trophy as this car has been fully prepped.
DSP will allow you to do a lot with tires. I'm looking at keeping my 245's on the rear and getting some 265/larger on the front. Just have to find some wheels with the right offset. As for the 2nd gear issue, I have the same problem. This only happens to me when braking hard on an uneven surface. My current solution is to just keep a hand on the shifter and hold it in 2nd during these parts of the track. I've gotten so use to the sound of it popping out of gear that it's almost natural to just put it back in while driving. I ran this past weekend on a smooth surface and had no problems. I am thinking about removing the shifter weight and seeing if that helps.