I love racing games as much as the next guy (hell probably more) but for some reason racing games on handhelds don't do it for me. I really like sitting in front of my TV on my couch with my wheel.
I think part of the problem is its extremely hard to be precise while in a moving vehicle. One pothole at the wrong time can ruin your wipeout lap. Burnout will probably not be as bad, (requires less precision) but I don't even try and play wipeout while moving anymore. Also it doesn't bother me that much but looking at wipeout while the car is moving around kind of makes you sick to your stomach!
Not to mention I already own burnout, wipeout, colin mcrae rally, WRC, GT3,4, ect on the PS2....
but what the hell right? I'll probably buy it anyway (unless of course its $50)
edit: ah looks like it will be $39.99...
another thing that bothers me about PSP racers is the lack of proper analog (gas/brake) and lets face it, not that great of an analog sterring input. For arcade type racers this is not that big of a deal... but GTmobile, I worry about.