No i didnt, but i doubt theres any difference.
Personally?, i`m going to only use Premiums still i have a nice amount of cash, then i might start to collect the more rare standard cars, till that time i`m not touching `m.
Also.. imho F`d up that in between the 2nd hand store you`ll see GT1 cars, the F1 GT car etc etc.
in GT2 the 2nd hand store was where you found older cars you would normally find on the 2nd hand market.. not a friggin cars you would only find on a race-track.