You're not going to get an engine that is going to perform better than the 46 AX for a lower cost. There are similar engines that don't cost as much, but IMHO they aren't an OS. Now on the subject of swap meets. Personally, I WILL NOT buy an used engine unless I personally know the person selling it. An engine can be ruined with just one or two lean runs. There will be a lot of engines (not all of course) sold at swap meets will be pretty much used up. There are those that will disagree with me, but I just don't like taking the chance of winding up with a dude of an engine. I would rather just spend the little bit extra and have a brand new engine. That way I know everything about it's history, since it doesn't have one before I acquired it. For beginners in the hobby I strongly advise against buying at swap meets because it's even harder for someone just starting out to spot problems with a used engine than it is for an experienced pilot. Of course the choice is yours to make, but if I were in your place I would just save a little extra money and buy a new engine.

That's my 2¢ worth.

Ken