I have used the GMS 47 muffler, which is similar to the Tower. On a 46AX and found the AX picked up some power in the upper rev range. It's claimed peak rpm will also increase and while I didn't tach the engine it did seem to have the often quoted 300-800rpm extra. I'd say mid range improves slightly, throttle response generally, and upper end is the main improvement.

The biggest improvement you'll note is that you won't be losing any more of those AX mufflers because of their hopelessly inadequate through bolts.... [:@]

As the GMS/Tower mufflers are generally longer, keep an eye on mounting space. Side mounts with the muffler running under the bottom of the fuse may foul wing saddle mounts etc.