The reasons why Bilstein won't "fit" has to do with the bushing mount on the lower eyelet. The strut mount bracket on the LCA of the Z62/Y62 is slightly wider apart. Here's how I know

The lower eyelet bushing on the OE struts are roughly 8mm wider than the Bilsteins.
I installed these B8 6100s over a month ago. All I did was add a couple 1/2 SS spacers to fill in the gap on the LCA strut bracket. I bored out the holes to roughly 14mm in order for the bolt to pass thru. What I also found out, since the top strut mount is the same from 04-current armadas, titans, qx56/80 non-HBMC, so are the strut mount rubber bushings. In other words, if you were to replace just the top strut mount from Nissan, for a Y62...it would cost almost $50/each. Don't even get me started on the spring seat and strut rubber bushings. I paid right around $60, Rockauto.com, for new Moog strut mounts w/ spring seats and KYB strut rubber bushings for both sides. What a huge difference it made on my QX80. The ride feels firmer but not jarring and when driving over multiple road construction plates, the truck still feels so planted. I knew these B8 6100s would be overkill but I'm sure they would show their true worth for those off roading with their trucks.