I just did a Painless kit. 10110. Nice product, but as you see rather pricey. Since I have all 'glass I think the Centech might have been better for me. I MAY have gone overboard w/adding ground wires, but that seems to be about 70% of all problems us owners face.
If you can, download either companies installation instructions and READ them until you almost have them memorized. Then it's just 1 section at a time, so don't be intimidated.
Good luck, and let us know how you make out.
I've also learned that sometimes... when people don't agree with you .... its best to hold them down and kidney punch them till they agree with you