Depends on what power you want to make, a standard wrx top mount is
good for 330/350 bhp, but a sti one is better for cooling and will run 350/400
bhp.
But seeing as you have a nice wrx just fitting a sti top mount will be
enough [Y] your engine will only take around 300-330 bhp before
it starts to get stressed and ready to go pop.
But then again if you rebuild with uprated internals then you can push it a lot more and then a front mount will be needed []
Id go for a nice tdo5/20g turbo, full decat, induction, uprated
injectors and a nice ecu remap by a top mapper ( andy forrest/bob rawle
) and have a nice 330-350 bhp engine
Depends on the route you wish to take, all down to money []
Tony