Please post examples. Models of cars that are also in GT5 would be best for comparisons. I'm about as far from a GT fanboy as you can get, but I haven't seen much that compares to the visuals on premium models. I would really like to see some of these models, if you can't hotlink photos just a link would be nice.
If your aiming at my point about it being to expensive, I'd say that still stands. Even if it's possible to do in a week, that's 40 hours of billable time someone has to pay for. There would be no reason to do this unless they made money off of it. People who work for PD probably get paid a decent salary. If you have a single worker who can bust out cars of premium quality in 40 hours who gets paid a totally crappy $10/hr that's $400 someone has to pay. I believe $10/hr to be an insane underestimate, I believe 40 hours to be below the required time, and even then what gamer is going to pay $400 bucks for a single car DLC? People bitched about the $5 car packs forza had.
In any event, the OP clearly misread something or read a total rumor so this is all moot.