APC 12,25/3,75 prop, A3 plug, High Power (Cool Power) 7 % nitro, 18 % synth. oil, stock muffler with baffle. Sea level 2 degrees C.

11600 not peaked.
EDIT: Whoops. 11600 was at screaming peaked setting! Let's say 11400 not peaked

Same but with a noname flat disk quiet pipe.

13300 not peaked (42 cm). I will make the length 45 cm (12900 RPM) to have a perfect pipe length for vertical and 3D flying. Perhaps some small adjustment when I have made a test flight.

EDIT: That is the same RPM increase I had with my Super Tigre GS 45

Edit 7/4-09: It is a MY Tuned pipe if any of you should be interested, see picture

Cheers