To my knowledge, no used car dealer is particularly 'competitive' when it comes to finance rates, it's down to you as the buyer to negotiate a lower rate.
I mentioned earlier about the general pay structure at used car dealerships. The base rate from the finance house depends upon the age of the car among other things.
If I were buying a used car, knowing what I know, I would decide how much I want to pay each month, arrange finance myself (my bank, online lenders etc..) and then go and have a fight with a used car dealer in order to get the price of the car down. I would try to avoid any gimmicky offers some used car dealers offer (0% being one) and concentrate on getting an honest car at a fair cash price. (If a car has just arrived at the dealer, it will be costing them less than he same car that has been sat on their forecourt for 3 months and so may do a quick deal for a 'scratch on the pad' so keep your eyes peeled for those).
Main dealer used car pitches tend to be the most receptive to lower rates, try heading in 2 or 3 days before the end of the month to close a deal. We all do silly deals to meet our targets.....
Jon
You gotta tie yourself to the mast my friend, and the storm will end.