I like your thinking scommer88.
I am looking at the 3" FTP mirrored finish Al jobies....but can't stop thinking back to how much engine heat they are going to pickup. Jeez they would look nice tho.
There is very little physical load on the intake pieces.
The Si can provide the structure, slipperiness along with the insulation, shame it doesnt come in a mirror or at least a paintable finish....or then again these days....maybe it does.

If you have the patience....I'd be inclined to use 2 suitably sized elbows and try the cut and glue technique using a compatible high end "high extensibility" silicon RTV, possibly like that you use to seal your bathroom corners etc.
The trial and error process could get pricey though.
Its the sort of thing many must gone and tried long before you = google and good luck.