Well, consider that the 1991 LA 5.2 with the TBI was about 170HP, and the 1992 Magnum with EFI was about 220HP ...Would a TBI conversion be worth it
I'd say "Depends. If you want to make it a slug, reduce the efficiency, increase the emmisions, and just basically toss a monkey wrench into its performance ..."
Naw, what you want to do is to upgrade to the 1996 OBDII wiring so that you can use the Flyin' Ryan tunes, or if HemiFever is still tuning.
You can tune the SBEC that you have; there's actually info out on the web for that; but I'm not one to suggest that lightly due to the fact that as far as I can tell (PLEASE prove me wrong, TazRango!), you can't just buy a tune for it.