I was going to go with that kit, but decided to go with the SP63 for the following reasons.
All exhaust and turbo components are either ceramic coated, polished. This will help reduce the underhood heat which is substantial on a turbo. The turbine housing will typically rust and look very poor within a couple of weeks on the RPS kit. I have also heard of some cracking on the RPS header. The SP kit uses a header with thicker tubing (and larger diameter) and thicker flanges. The SP kit also has a superior wastegate and blowoff valve. I also believe you get a bigger/higher flowing intake with the SP kit. I was sold on the RPS kit and didn't think you needed all the bells and whistles of the SP kit until I started doing a little research. Now it's apparent that these bells and whistles are more important that I had initially thought. If you bought an RPS kit and tried to upgrade it to this level, you would probably have spent more than just getting the SP kit to begin with.
Later, Steve