As long as you know the guy is a reputable dealer there is really no issue here. You can do some more checks with the BBB and the State DMV where he's doing business, but if like you said he's been in business for three years and is still going you should be just fine. As for how you get it licensed to drive home, if he's a dealer he'll be able to issue a temporary permit for you to drive it home. Based on your description this does not sound like a scam at all.
And cashiers checks and guaranteed funds and all that can be forged by the buyer too. Not to mention not only does he not have the time to go cash your check and put a wad of cash in his pocket, he probably doesn't want to deal with cash anyway. He'd rather just deposit the check let it clear and then send you the title. Transactions are done like this all the time through dealers.
