2003wrxwagon

I've just purchased my first Scooby and love it already, two questions, its a 2003 blob wrx wagon. I plan on fitting my Parrot hands free and will need to remove the standard head unit. Is it coded and if so where will I need to look for the code.
The car is standard bar a exhaust, fuel pressure reg, panel filter and a forge dump valve, all great apart from the later. Can I just get hold of a origanal valve remove the bung and valve or will it destroy whatever map the car must have had.
If so the woosh may grow on me.

Kedlestone

iTrader: (9)

Fine to put the oem recirc valve back on, it won't have any ill effects.