[Zero10]

Even with the biggest turbine housing available, max compressor speed will still limit the amount of boost you can make.

With the wastegate line pinched off (or in my case disconnected), the max boost a K26/6 will make is 23psi, and after 4000RPM you will see it start to fall off to around 7-9psi at redline. If you want to run 15-17psi, it's adviseable to upgrade the turbo. A possibility is a K26/7 or 26/8. However, a lot of guys are using garrett turbos with great success.
The numbering is as follows K2 - cold side intake area (cm^2) - / - hot side intake area (cm^2). So, a K26/6 has both an intake and exhaust area of 6cm^2. That's how I had it explained to me at least.

With unknown chips, and a fubar'd stock boost management system, I would estimate I was easily clear of 300hp. That's with a peak boost of 23psi in the mid-range, tapering off to about 8psi at redline. It would light up the tires right into 3rd gear, until past 5000RPM. It was just scary fast. I've seen people getting over 300hp at 18psi of boost (320-340hp)