engine selection
 

I just purchased a zen 90 great looking kit my problem is seleting an engine. i am leaning towards the ys 110. i was wondering would the long quiet muffler with a flex tube and a 90 degree header made by mac work if the engine is mounted inverted.

If i went for the two stroke os or supertiger 91 mounted inverted i was wondering if any one knows where can i purchase a header which would work in this situation if i were to use a tuned pipe mounted inside the belly pan.

does any body make a swan shaped header for a two stroke 90 size.
thanks
zain