Get your manifold, downpipe, and turbine housing ceramic coated if you don't want them to rust.. It'll help with underhood temps too. The turbo blanket Kirk mentioned is also a good idea. If it were me I'd get everything heat coated and then put one of these on the turbine housing:

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS


IMO heat wrap on uncoated steel will only help it rust faster.