A year later & I'm the first one to post? Wierd...
Here's my Sig 522 S.P.A.N.K. version afrer retrofitting a Sampson Star quad rail & the heavy barrel on the classic frame. Troy Micro sights, Aimpoint Comp M3, LaRue FUG & Magpul AFG2.
Sorta my version of a zombie-go-to gun. Well, I might take the Aimpoint off & put the 16" barrel back on & run everything open - I do love that look too.
The 522 BUIS version - The Troy Micro Battlesights are unbelievable - totally worth spending $160 on the Sampson Star 522 quad rail in order to use these sights. Even my 62 year old eyes have no problem lining them up.
the sling is Israeli, for the Galil (have a couple). but it works really well for the 522. it's sometimes called the galil / israeli quiet sling because nylon ropes are used to tie it to the gun. so its less noisy than a metal hook to the post setup. or if you don't like the wear of a metal hook to the sling loop/post, it also serves that role well. they can cost anywhere from $10 to whatever. some come with Israeli unit patches sewn on so they cost much more. where to find? I don't remember as I bought mine a while back. but u should be able to find them using the search terms above (along with IDF, IMI).