Yes, the taller the shackles, the more the spring pack is pushed down in the rear, a.k.a. "flattened out."

I've only done the shackle install and it was pretty painless and quick. Go figure, SLR sent me the poly bushings after the install as I couldn't wait, I just haven't put them in yet... But that's neither here nor there.

I haven't installed the AALs yet, so I'm not sure how involved it is - I don't think it's that much more work over shackles, though.

I think the AALs are the way to go, and I also think most would agree?