You normally do not need to extend the driveshafts with a 6" suspension lift on the 80-96 Bronco. I have not seen near enough flex/travel out of the typical kits to over-extend the slipshafts (except the kit from AutoFab). In any event, though, you need to cycle the suspension fully after installing the lift to make sure it will not happen. IF you get really close, you can use limiting straps or have the ds extended up to 2" in length. If you make it too long, it will jam up and damage your t-case or differential. A 6" susp lift kit is usually $25-$50 more than the same 4" kit, but would work alot better with extended radius arms. So you're looking at $950-$1100 for a good, driveable 6" kit vs the basic $450 4" kit. Lastly, a 4" suspension lift and 33" tires is the best combo for street and offroad, in my opinion (IMO). But most folks you talk to with a 4" kit wish they had gone to 6" to start with to get more room or flex or both. I went with the 6" kit right away on the 84 Bronco, with 35" tires, and that's about as tall as I'd go without having to use some kind of ***** steps to get in (I'm an old man, OK>!) I have about 5" lift with my SAS on 36" tires which is about the same height. JSM84