The poly bushings squeak unles you lube them on a regular basis. As for lift and how much you get, it is dependent on which part numbers you order, they have a Light duty and heavy duty, the LD gets about 2.5 the HD is reported as getting 3.5-4 inches. Have a set of drive shaft universals handy, if you get bad vibes replace the rear universal first, generally when they have been 'happy' at their current angles for thousands of miles they tend to pitch a bitch when you change the angle with a lift, sometimes this solves the problem, sometimes not. Also the lift will settle over a few days or weeks, depending on how much you use it, so be aware of that too....