The shackle / hanger part won't change your ride other than you'll hit the bump stops on nasty bumps.
with 2" coils upfront and factory shocks, it rode just like stock. I stepped up to nitro drop shocks, firmed up the ride, but the handling was downright amazing. Totally worth it.
I caution you on the shackle / hanglers. They are a total pain in the ass to install, and I think you'd be far happier with a flip kit in the rear. You can but a frame notch for about $150, and a set of spring perches for $25 from Summit / Jegs / Etc. You'll be far happier.
The "4"" rear drop is more like 3 at most, and just doesn't really look 'low' IMO. The flip kit is supposedly 6" and was more like 5". I did that and 3" coils upfront and loved the stance. IMO it's the way to go!