Do I Need a Customs Agent?

[Concordia]

Hi All - Our cutter is in Mexico, but its Bukh diesel engine is here in California. As the engine appears to either require a complete overhaul or replacement, one of the options to consider is buy a used motor from a lifeboat removed from a ship sold to a dismantler in India and have it shipped to California. This is the preferred approach over buying a new engine, such as a Beta, as there is no professional support in Mexico when I get in over my head. Should I hire a customs broker or do it myself? The seller included a comment about EPA clearance, but no detail beyond that. My guess is that since the used motor isn’t EPA certified, I guess I’ll have issues?