There is a bended piece of alu pipe with a flange that bolts to the engine. This thing is called an exhaust header... the tuned pipe is connected to this thing by means of a piece of silicone tubing.
You can change the tuning length of the exhaust system to a higher rpm band by cutting a piece off the header or the pipe.
The engine-pipe combe that comes with the Magnum is already tuned pretty well (that was the whole idea of the thing... no fiddling with the tuned pipe...), but there are people on this forum who seem to think there is more to be had from this engine.
So when this thing is properly run in, I'll start taching it, and tuning the header length for max rpm... rpm=SPEED...
hehe
By the way... the tuned pipe is held on by some wire straps. Now I used a pair of tweezers to tighten them straps, but the pipe still came loose the first time I ran the engine. So I retightened them right after they came loose, when the whole thing was still very hot, and it hasn't moved a bit since... I guess them things just stretch a little when they get hot, and when you retighten them when they are hot, you take out all the stretch. (they streched almost 10mm actually)
In the manual is stated you should use epoxy to hold the pipe connected to the header... I don't like that... how can I fiddle with the damn thing when it is glued stuck?