One strategy you can try is to make friends with a used car dealer and offer to drive back cars for him, and also pay him a fee for him to get the winning bid on a car you want.

Most of these dealer auctions have an inspection period for a couple hours prior to the bidding (by the dealers only, usually, not their jockeys). You may need to rely on your dealer to pick out a good car for you.

The risks in this auction come in when you understand that the unscrupulous guys actually tamper with the cars they want to bid, making them less attractive to unaware other bidders. When my security guard company (my employer) had the big auction in Manheim, PA we routinely staffed about a dozen guards in the lots for the express purpose of watching the dealers as they inspected the field.

The general impression I took away is these auctions are mostly dealership "rejects" -- trade-ins they took to close a seal but which do not fit their line or meet their standards as a "cream puff". Also, they are from other used car dealers who couldn't sell them and now want to refresh their inventory.