Hi!
Glad your first flight with the new OS was successful!
Put on a decent prop (MA are one of the worst) like APC or the black Graupner "Cam-prop" and you will see more speed. 10x6, 10x7 might be good for sport flying and 9x6,5, 9x7, 9x8 for speed.
If you want even more speed, get a tuned silencer (magic muffler) from Dave Shadel at Performance Specialties in Nevada.
Worried of destroying a plane??? Planes are supposed to fly and pylon racing is the ultimate thing in this hobby...And I have 4 more of those Tigers...!
Here is the one I won the last two races with. I have had it for 3 years now. The model is called "Ryggskott" in Swedish (Lumbago=backpain). It's a kit, made from the original Q-500 model in 1968. Engine is Webra .40 GT and prop is a Graupner 10x6 "Cam-prop". Speed is around 180-190 km/h.