well copper is metal...
so your title is alittle weird.
but anywho.

if your going to run some big time boost, then go with a copper head gasket.
they cost some money tho...
a nice steel gasket wont cost quite as much and will seal just as well and perform just as well under normal operating conditions, even under elevated performance conditions the steel gasket will still do the trick.

i mean ill be running 32psi and im rocking a 3 piece steel gasket.im not a fan of copper gaskets because they seal to well.
id rather blow a head gasket instead of a motor...
not running a copper gasket can act as kind of a safety in a sense.


but the point here is what kind of power do you plan to make and how are you going to make this power?
motor swap, t78, t88, huge turbo? nitrous?
big ass turbo with a shot of nitrous to help with the spooling issues?
lots of info left out that needs to be taken into consideration before making a decision.