ORIGINAL: Harry Lagman
The AX is slightly more powerful than the TT (12.3k versus 12k with an APC 11x6) and both will pull about 1000 rpm more than an SF with an APC 11x6.
If you want approx 1,000 RPM gain on the .46SF then get a "Tower Muffler" and bolt it on. You will easily get the SF up to the power range of the ax & tt on stock mufflers.
Here is a link to the [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJB16&P=C] Tower Muffer[/link].
If you want a whole lot more power in the same class and are willing to pay for it, then get an Irvine .53, OS .50SX(My Fav), or a Webra .50