The rear axle will be off set a little, I have about 120,000 miles on my lift with no problems though. I still have the original C-V axles also. With 4 inches of lift I can't go down the freeway and 75 MPH with the hubs lock in, they start to vibrate about 45 or 50 but with all the wheelin Iv'e done they have held up well. If you look at your C-V axles stock the center line of the dif is lower than the center line of the hub. With a 2" lift the axles are at the same angle, just reversed. So in theory a 4" lift only increases the angle of a 2" lift. I have not had any problem with the rear drive shaft, with a 104" wheel base they are long enough.

Hope this helps, Dennis

95 Sportage, gone but not forgotten.
98 Jeep TJ, 4" Zone springs with RC Long arms, Ford 8.8", 4.56 gears & Detroit locker rear, D30, 4.56 & Detroit Trutrack front.