Transfer pipe- can only be found at main dealer or heebay for ex-dealer stock (as far as I'm aware)
Stat -Wahler or GM for the thermostat (Wahler is OEM) about £20
PAS Fluid - from your dealer £4.80 trade price (why get it elsewhere at that price)
Drive Belt - 6PK 2020 from any motorfactor. (that's 6 x grooves and 2020mm long) genuine GM will be about £28, independant Gates cost me about £18. Gates is a very good make, probably make the GM ones!
Timing Kit can be any make. They get advertised as GM, Contitech, Gates, SKF - made. ABout £100, but there was one found on Amazon for something daft like £50 and used wityh good results, Someone might be able to direct you to this. Nomatter which kit you buy, even if it's for the 3.2 can be 'made to fit' any other V6, by reusing your existing backplate, so you can't buy the 'wrong' kit even if you try. (famous last words)