this is not meant to be advertising, I do not profit in any way from this product, but I have been using one for over 3 years on all my 3d planes and consider it to be required equipment.

Everyone knows that most 3d stuff is much easier with a light plane over a heavy one. also it is necessary to hover at 1/4 to 1/2 throttle so that you will still have explosive power to instantly recover when needed. I see too many 3d-ers go to a bigger engine than is recommended which adds too much unnecessary weight. the answer is to turbo charge a smaller/lighter engine. I have been using an escomposites carbon fiber tuned pipe on my diablotin for over 3 years now with excellent results, see pic below.

Advantages:

1. on my os46fx the mac header, coupler, 2 spring clamps and cf pipe all weigh 20% less than stock muffler that comes with the engine!!
2. the cf pipe boosts the power 30% over the stock muffler - makes it perform like a 61
3. it is specifically designed to promote a linear throught curve - which is vitally important for hovering and other 3d stuff.
4. it redistributes the weight back off the nose of the airplane
5. it is very quiet for hovering next to your ear in a park or backyard. (quieter than an electric with gearbox)
6. less clean up after, no oil on front of airplane or wing area.
7. nearly indestructable, I had a crash, lost everything except pipe was undamaged. it will virtually last forever.