PST has an aluminum caliper upgrade kit ( ALU-MAX ) with two 38mm pistons ( for manual brakes ), or two 43mm pistons for power brakes. They come with high performance brake pads and hardware, and you can use them behind 15 in. wheels. You can also get the slotted rotor kit and get $50 dollars off. The total cost would be $668 W/ free shipping. I've never bought from PST and have no idea about the product line! What do you think?