Well I have tested both against each other and they were VERY close on a 9x8 APC 200 rpm's maybe? I'll check when I get home...

The Rossi-was on 5% with the stock mini-pipe, the LONG pipe Dave mentioned would get you higher rpm's with some extra work, the OS-50SX I ran with a Tower muffler so the Rossi was stronger based on stock muffler and lower nitro, but they can be made pretty even with fuel and exhaust choices-- I love both mine!

The Jett-50 is FAR & AWAY the best choice but $$, the Webra-50GT I tested was stronger than the Rossi and OS-50SX mentioned, and is lighter (Key on the F-20 or Patriot style long-nosed propjets) and also runs on 5%

The YS-45 w/Macs 7.5CC pipe would be my 2nd choice behind the SJ-50, and the West-50 is supposedly a monster but again has the long pipe to tune, and accomodate-