Ive only played Forza a few times, prefer PGR4 and Grid from a "pick up and play" point of view, although given the reviews of Forza on here and the endless custom cars i keep seeing, i better get it dusted off!!

How long to the cars take to get to that sort of standard (as above), and how do you go about getting the company logos on there etc?! Like the smirnoff one for example?! Im sure its not that hard but i havent tried yet so would like a bit of a novice guide!