I'd really like to allow selecting any car, Premium or Standard. There are so many good cars in the Standard car dealerships.
I posted a site a while back that will tell you exactly which day any car will show up in the UCD. From there it's a simple matter of going through the license tests to advance to the day the car will show up. I know it's not ideal but it is a relatively painless way to get a car you need/want. I used it to complete my Standard car collection.
I know I'll probably get shot down, but I thought I'd throw it out there anyway.
I never know when the OCD is going to refresh, I wait for Vol to tell us