For <$350, there's a guy over on BenzWorld with his own machine shop, who will do a complete port & polish job on your heads, intake manifolds, do a tapered bore for your throttle body, etc., etc. Personally, I'd do that way before I'd pay $80 just to clean up the heads. You will probably pick up a little power too.

His name is "NEOKEN" he's one of the mods on the R129 forum. He does good work, hit him up. Shipping's not that bad if you go with UPS ground or FedEx freight. But if you need it fast, then it's probably best to stay local.