I along with 2 other RC flyers paid $75 for the new Raptor II engine introduced on RC Online about 3 yrs ago. The Raptor II ran into production problems so the dealer (Sky Hobbies) offered our money back or a GMS 47. We all took GMS 47's. I never used mine but the other 2 installed them on Hanger 9 Adnance ARF's. One of the engines connecting rod broke at the bearing where it connects to the crank. Later found out the rod was welded at the point where it broke. The other guy tolerated his GMS for a few months and re-installed his 46FX. Mine is sitting right here in the box. The head is still gold, the shims and muffler are still unused. I fly 2 Dazzlers: one with 46FX and the other with a 46SF. The now defunct GMS 46 (now the Tower 46) is an exact duplicate of the OS 46SF.