Intercooling
 

Can aluminized steel pipe be used for intercooling? or is aluminum used typically for a reason?

aluminum is the best to dissipate heat

or is gold better?:P

Copper works quite well.

To plumb the IC? The steel is heavier, but it works OK. I am using it in my system, but my IC tubing is only about 10" long.

Aluminum would be my choice, then copper and finally aluminized steel.

Well, the damn car already weighs 4900Lbs so I don't think that weight savings is a concern.
would there be enough oil vapour within the sytem to prevent the inside of the pipe from rusting?

It's not as much about the weight of the car but weight the connecting boots must support.

If I didn't want to fork out big $$ for a new aluminum Intercooler, which car is the best to take one from? Saab? Subaru? Volvo?

Saab

Yes, Saab. But don't use the cast aluminum tubes that Saab does. They only have a 1-5/8" (41mm) inside diameter and the 617 needs a bare minimum of 2" to breathe.

Im plumbing a deutz oil cooler, cleaing out the insides and usuing a water to air intercooler, its all alluminum and deutz made it extremely efficient at displacing heat, so it is about 8 inches wide and about 13 inches long, and has about eight cores.

Boneyard intercoolers are fine but if you check Ebay there are many, many, many IC's for sale and some quite reasonable. RT

Which Is better?
 

Air to Air?
or
Air to water?

air to water. you can cool water much more than the outside air is.

Air-water is best for this application only because of the very limited space available. But, it will never get the air as cool as the outside air unless you use ice.

Air-air is the most efficient if you are not afraid to alter the body for it to fit.