I haven’t found that to be the case at all. Lowered about 4” up front using lowering keys the CV angles are way better than a cranked up 3” lift. The only practical limitation to lowering the front using lowering keys is ensuring that your alignment shop can get things in spec. I used lowering keys, got an alignment done and had no cv joint issues.
I can adjust my front drop from a 3” to a 5” using the keys. In the end after some trial and error I set it at about 3.5” drop and had the alignment done. I only did a 3.5” rear drop so that played into where I ended up plus I was looking for a slightly higher in the rear setup that sits fiat with 500 pounds in the box but each to thier own.
That being said the most ideal way to lower the front 4 or 5 inches is to use the 4x4 99-06 drop spindles along with stock de cranked torsion keys. The 2” drop spindles raise the wheel up in relation to the suspension allowing a drop without changing the angles of the suspension. 2” drop from the spindles and de crank the stock keys and voila you are at 4”. I’ve never done it but it’s not a hard swap to go to the 99-06 drop spindles and other associated parts. Look into the 99-06 brake upgrade and you can copy all of that but using the drop spindles:
Credit goes to Rocky Thornton: If you do this brake swap on your OBS truck you will be amazed at the difference. Your best bet would be to go to the auto salvage yard and buy a pair of steering knuckles complete with hubs, brake rotors, calipers, ABS sensors, etc. I got mine off a...
www.gmt400.com
Also noteworthy is that although I could get a 5” drop with my drop keys my wheels had a negative offset so I would have rubbed on the fender when turning over bumps. Factory wheels would “tuck” easier. In the end I was fine at 3.5” but I didn’t do a 6” rear drop with a flip. I did the adjustable rear shackles and lowering hangers for the front of the leafs. It worked for me.