Also, don't be afraid to try an APC 11x5. I run that prop on mine and I get better climb and the same level speed as with an 11x6.

The reason is that the 11x5 allows the engine to rev just a little higher, but it's enough difference to make up the airspeed loss from the 1" of pitch, while at the same time, the lower pitch gives better acceleration and climb.

Alsok the Tiger isn't exactly a low-drag design, so the lower pitch will help there as well.

Also, if you want more power, take the baffle out of the muffler. It makes the engine a little louder, but the pick up is noticeable.