Why do you feel you need an upgraded diverter valve?

Unless you current valve is leaking OR you are planning to chip your car, it is unlikely you will notice any difference.

 

You defenitly won't notice a difference. They really aren't performance oriented. They're more of a safety product.

Unless I'm not understanding this well, all they do is relieve pressure from surging back into the turbo, thus making less wear to the turbo and resulting in less lag.

They divert the excess air after the throttle plate is close, slow it down and return it back to the charge pipe.

An aftermarket one really isn't necassary unless you like the cool. pppppsssttt sound.

I knw a kid who was bored one day, and duct taped a turkey call to his BOV. Everytime he let off the throttle all you heard what thje turkey call. lol