I installed a set of Steeda
Sport Springs. They don't show up for 2006, but I cross-refferenced them using Ford Racing Parts which shows a
similar kit for '05 & '06 using the same part number - So I figured I was safe to use the '05 kit from Steeda.
The install was
very easy. I did the front's in about 30 minutes and the rear in about 10 minutes. Total time, including bench racing with my buddy, was about 2 hours.
Before
After
I am VERY happy with the result - Not too much, but not too little. The car sits level and looks good (although dirty right now

)
For more detailed pictures of the install, you can visit
my Web Site
(I posted his at Corral as well, but thought I'd put a thread here - can't decide which place I like better

)