a real p90 is made mainly of composites... there's not a whole lot of metal in it.
A full metal gun would not exist.
An airsoft version with a metal receiver exists... there are several in fact. The only non metal receiver being from TM and maybe echo1/ks.
It is this online community's policy that non age verified members can not be told specifically where to buy guns.
In addition, for importation regulations, a 350fps airsoft gun would not be allowed in country by CBSA, and would be considered a replica and a prohibited device. You will not be able to buy such a gun from a retailer.
Should you find a retailer that stocks p90s, your only option is to install a new spring to get your target fps.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.