I'VE JUST BOUGHT A CERMARK SUKHOI ON EBAY. I WAS GIVEN AN OLD ONE BY A MODELER FRIEND AND IT FLIES LIKE IT WAS ON RAILS WITH A SAITO 91, ALTHOUGH I FEEL IT IS A BIT UNDERPOWERED. WOULD LIKE TO USE AN OS 120 FS W/PUMP THAT I HAVE LYING AROUND ON THIS SECOND ONE. ANY THOUGHTS ON THAT?