Something is wrong. It should be almost instant. I have probably 300 cars or so in GTPSP, and it took seconds to move the list over. I'm pretty sure all it does is takes the text names from your PSP garage and looks-up and imports the cars in GT5, so there is very minimal of actual data transfer.
Just make sure that you've gone into your GTPSP menu to begin the transfer, as well as the GT5 psp-sync button in the settings menu. They both have to know that they're transfering together. I waited and waited for mine originally to pick up the GTPSP game, realizing later that you just have to initiate on both ends. After that, the transfer was instant. I just don't like that you can only choose 50 cars to be available in arcade mode. Why not just transfer all of them to be available in arcade, since it has nothing to do with your GT single player game?
Anyway, hope that helps shed some light.
