A BOV and a wastegate are two different things, but I'm pretty sure ALL turbocharged cars nowadays, including the Stagea, have both fitted. I might be wrong, however...
A BOV releases boost pressure when you back off the throttle, giving you much-reduced reversion and therefore better response when you back off the throttle (like during gearchanges), but a wastegate (which is almost always internal on a factory-fitted turbo, as it's a cheaper and more convenient way to mount it) controls the level of boost when you're ON the throttle.