The AXE Rossi are wonderful engines. The side exhaust AXE Rossi engines, especially those with the VP mod are probably superior to "most" production side exhaust engines.
Sadly, there are no new AXE Rossi rear exhaust 60/61/65s being made, as far as I know. It seems to be mostly a matter of what is available in the configuration that you personally wish to use
I think it is great that NovaRossi, YS, SMT Distributing, LLC, Richard Verano and others have taken it upon themselves to make rear exhaust engines available to the Classic Pattern community. We no longer have to search the auction sites for worn out, overpriced engines! Wish Enya could get their rear exhaust AAC 61 back in production.
Jim