The lift kit would not affect the driveshafts. It would only drop the suspension. The rear end and front diff are mounted in the frame and it won't change them or their driveshafts or angles of any of that.I would be very wary of adding a lift kit. Anything that modifies driveline angles likely will stress those parts pretty badly in hard use. I do not think the rear drive shaft drive system will tolerate much deviation from the stock angles. Front driveshaft may not be so bad as it has u-joints on both ends, but stock, the front drive shaft is nearly straight shot too.