P-38

Aluminum.
Or you could go with Bare Metal Foil.
But I would recommend Tamiya Aircraft Aluminum from the rattle can for a trouble free finish.

Don

This has been covered pretty well in prior postings, but if you have an airbrush the best choices are Alclad II ( various shades of Aluminum ), ModelMaster Aluminum, and Floquil Old Silver ( model RR color ). The Alclad II is arguably the best but arguably the hardest to use. I've used all three with good results.

Rick

I've used SnJ with good results (the aluminizer). It can be used undiluted right from the bottle, and doesn't need a gloss coat underneath, but looks a little pebbly if you don't.

Different shades of Aluminuim or /and steel at various panels, burnt metal/exhaust for the turbochargers.