How does this work as a scam?
If he were offering to sell exhausts I could see someone taking your money and not sending you anything, but if he's asking for an exhaust wouldn't you get the money off him before sending the exhaust?
And I have a used set of mufflers but shipping from Australia would be stupidly expensive, but if you want to send me all your credit card details and all your banking passwords, as well as those of your family, then once I've finished my shift on an off sea trawler on overseas deployment on it's way to a Nigerian oil rig I'll gladly send them to you.