where they are puchasable from?

also what wall thickness does the alloy need to be? 2mm?

a friend is looking at adjust his intercooler and needs a 90 degree bend

I've search ebay and they are around 1.6mm?

edit to add

though just found this, i assume would be ok?

http://cgi.ebay.co.uk/64mm-2-5-Aluminium-Alloy-Intercooler-Pipe-90-degree-/300519233149?pt=UK_CarsParts_Vehicles_CarParts_SM& hash=item45f857967d