It is ONLY my opinion about the RS2000 being lame, maybe I was expecting too much after my x flow, 170 AUTOMATIC, which slaughtered my mates RS2000, after him giving it all the gob, I was just of the opinion they could have been something a lot better.
As for your x flows, I can't comment as didn't build them, but it is without doubt one of the most tuned engines in history, and in 2 litre form(AX) kills any pinto easily for the money spent versus power.
I know it is ancient, but why fix something that does not need fixing?
tabetha