What do you mean by a "stock" t25 (internal wastegate I assume)? And why don't you wanna run a BOV? A BOV takes the extra air that is built up and relieves pressure when the throttle plate closes......hints what eraser said. If you don't want the sound youtube them for a quiet one and run it recirculated, it'll be less annoying that way.

And if a BOV is out of your budget, you shouldn't be boosting anyways