I'm pretty much between the Magnum XLS-46, SuperTigre GS-45, and SuperTigre G51. On RCU's reviews page, the SuperTigre wins out, mostly to leaky carb on the Magnum. However, the Magnum is in stock now, and has the rear needle adjustment (which sounded good at first). SuperTigre's appear to be on the heavy side, so the G51 is appealing in that sense.

I am new- in the process of building my first plane: Hobbico Nexstar, which requires a .46-.50 size engine, so that's my first need. The RTF version comes with an OS .46 FXi, with a rear mounted needle valve; the reviews say a Magnum is a good substitute here.

The reviews are slightly higher for the SuperTigre .45, and even higher for the G51, which is lighter, but like Campy said, the RPM's are rated at 500rpm slower than the .45.

If you hadn't noticed, I'm buying from Tower because of deals they have and some credit I have left over.

Thanks.