The reason your diverter valves keep going bad is bad design by Audi. They're one of the worst parts on the car. They use a plastic housing and piston inside and it's just horrible. If you really want to fix the problem, I suggest an aftermarket one. Like the one Evolution Motorsports sales. wwwevoms.com. Great place for Audi. That was the first upgrade I had for mine, and I noticed a great improvement in turbo response and haven't had any problems in almost 20k.