I think its a heck of a deal, by the way, my expy stays around 13 in town, with the stock wheels and the 20's. I run 275/55/20 which is like 32inches with a heavy chrome wheel, and have toted my stock car (2700lbs plus trailer) with no problem. it pulls better than my 350 powered chevy, but stopping is a little more difficult. To me, as much as I love this truck, I would jump on it, and buy a tuner, and later on some gears to compensate for the big wheels, if it caught your eye, chances are you will be trying to modify anything else you buy, and thats more money.
Tell them to put some stock running boards on it, and roll it. thats my opinion.