There is an upgraded parking area called Easy Out or something like that. It is a section right next to the one exit where they funnel everyone out. Not sure what they are getting for that one these days price wise but it is worth being farther away from the entrance to save some time getting out but even then it can sometimes get clogged up there as well depending on how fast you get out to your car and how many tickets have been sold for the show.
Unfortunately the only way to really make sure you don't get stuck in the 4 hour grid lock is to leave the show a song early, especially if your show is sold out.