From my own experience (not my truck, but my buddy's truck) and all that I've heard, the coil spacer will not change your ride quality one bit. This is because it places no additional preload on your suspension parts; it just adds a few inches of height to the mounting surface (however, that also means you aren't actually getting any additional travel or suspension lift out of it). If you just want to get a little extra clearance or add some bigger tires, there's nothing wrong with a spacer lift/leveling kit.

However, I agree that you should get a quality diff drop kit if you have a 4X4, especially if the lift is over 1.5"

Good luck! <img src="/forums/images/graemlins/kewl.gif" alt="" />

By the way, my buddy used the lift kit from truxxx and has said it's a great product. Check 'em out if you're still not sure what brand to get.
www.truxxx.com