What are the EPA extra steps you have to deal with?
Industrial/agricultural engines don't have to meet the same emission standards as road-driven engines. Some people care about that- - - -others don't. Hotrodders who change carburetors, camshafts, and exhaust systems without getting their engines EPA-certified fit into the "I don't care" category. A lot of those regulations are there just to keep a bunch of bureaucrats employed! Just be aware that for every engine that fails to meet emission standards there's a possible $5,000.00 fine and 5 years in jail for the guy doing the modifications.
Jerry