Both the Magnum/ASP/SC XLS 52 and the Evolution 46NT are excellent engines. They are very popular in the US. Mufflers designed in the OS 46 size will fit the engines you desire also. These engine both also have the same mounting bolt pattern as the OS 46 FX.

I never seen but one VMAX/Tiger Shark (it was a 46). It ran fine but that's all I know. They are not any at my flying field. Tiger Shark makes a 56 or something close to that size that's been talked about some.

Enjoy,

Jim