Not to prolong the conversation (it has been a good one), but anyone interested in a GMPP turbo upgrade should seriously consider doing the sensor and harness install themselves using the kit from crateengninedepot.com. I've done it on 3 Sky's with no problems.
1) Buy the kit from crateengninedepot.com
2) Follow the GM installation instructions provided. When you get to those two sections that describes the soldering the the pigtails ----- skip that and just install the pigtails. It will take you longer to put your tools away and clean up than to do the install.
3) Take your Sky to a GM dealer for the re calibration. Make sure you take the serial number and authorization codes provided by crateengninedepot.com.
4) When driving to the dealership, Take it easy and try not to let the turbo kick in. You should not get any error codes or experience limp home mode. NO BIG DEAL if you do because the re-calibration process will clear all of that up.
5) Re-cal doesn't take long once the tech hooks up to the GM computer system..
I am not trying to oversell the GMPP, but previous buyers of my 2 previous Sky's were happy that the SKys' had the turbo upgrade and that it was ,in fact, a GM approved setup.
I really enjoyed reading everyone's previous comments.