i dont know personally how well they work, but i hear great things about them and plan on installing one over spring break. ill post further finds.[addsig]
I am pretty sure that with both of them you will need to sort out all of your steering issues. With a spring over you will probably have to flip your tie rods to the top, or just get the K-Link system on the same page of the Quadratec book. If they come with reengineered steering components then how could you go wrong for 5 inches of lift for under 400 bucks!