Been running my 4/6 McG' for about 4 years with no real concerns. Just FYI to inspect your factory perches and add welds to strengthen if need be. Also if you run 17's that it may or may not clear the drop spindle nuts so if you have clearance issues then shave the lower spindle nut until it clears. Again it is only if you are running 17's.
You most likely will need to swap our your factory front bump stops since those cans will be touching if not laying on the LCA. The McG' kit comes with rear bump stops so your set there.