You first off definitely NEED to get a new set of wheels, not just because they're hideous, butyou have to have the same size all the way around with an AWD car.
"With one tire significantly larger or smaller, the differential on that end of the vehicle will think the vehicle is turning -- one wheel rotating faster or slower than the other -- while the rest of the drivetrain thinks the vehicle is traveling straight with all wheels rotating at the same speed. This can put enormous mechanical stress on driveline components and lead to premature failure of expensive components."
Secondly, ditch the BOV, unless for whatever random reason the car is tuned for it. Any idea of any other mods that were on it? The previous owner just slapped on the turbo?