I like the idea of top-level racers coming to dice it up with us! I think it brings exposure that is good for all of us. Plus, how awesome is it to race against (and potentially pass and beat) the guys who get paid to do this?!
With that said, I don't think that just having pro drivers does anything for your team except guarantee that Judge Jonny and Phil are going to scrutinize the living hell out of your car. Remember the Channel 4 News team at ThunderHill '09? All drivers were professional drifters. They ended up with several penalty laps and finally had to put it on the trailer before the end of the race, which brings me to my second reason that pros won't come in and dominate.
Lemons racing is different from top-level racing (duh, but hear me out). It requires a different skill set, not entirely, but you need a few more tools in your box. Guys at the apex of motorsports pretty much all drive the same: really really well, with clearly interpretable intentions that allot for clean driving at 10/10ths. Us? Not so much. You can't just throw a guy who always knows what the driver in front will do (silly things like hitting apexes and such) against a pack full of parade floats and nimrods who have never been on a track before and expect him to do well. He'll no doubt be quick, but my crystal ball shows something black and rectangular waving at him.
-Kyle
Eyesore Racing
"That's probably wrong, but it's worth a shot."