FunkyBoy

It just means "western thing" (as in european/american). Like, western-style food, or western-imported stuff. He says that the best porn is the western one, basically.
 
edit: actually there's an entry for 洋モノ on weblio. This is just a casual モン instead of the full モノ.

Probably not, the game was only released in Japan so there shouldn't be any form of decensoring patch available as that's illegal there and it wasn't licensed by any western company so the uncensored CGs can't be made available.