Ok, so I was asked how I did the install on my car and decided to make an install guide/how to for the 2011 WRX. I'm sure its the same as the previous years but wanted to post my own. Perhaps it will help others.
First off, I went with a company that I cannot recommend. However, in the three short days I have had the kit installed, I have not experience any issue. I chose a 5000K with 35watt slim ballast kit. The kit included only the ballast and bulb, which naturally have the wires connected to each.
First step, I removed the back covers of the low beam headlights and removed the factory H11 bulb itself.
Here are the tools I used to make the holes on the back.
I then took the backs and drew an one inch circle, with a pencil, in the middle which would serve as the openning for the HID kit gromet.
Next, I took a drill and proceeded to drill a sequence of holes along the inside of the drawn circle. I tried to make them as close as possible to ease the seperation of the center part from the rest of the backing.
Once all the holes were completed, I pushed the center out with the back end of the box cutter.