You should be replacing all the connected parts. Springs should be ok to reuse. The original springs no longer made and aftermarket do not state any specs so stay clear of generic replacements.
You’ll need a spring compressor once the assembly is out or have a machine shop do it. Here’s all the parts. This is identical to my 09 Escalade that takes z95 inserts. It also shows an option to go with all aluminum front suspension parts.
Post in thread 'Aluminum / XFE NNBS Front Suspension Rebuild'
https://www.tahoeyukonforum.com/thr...-front-suspension-rebuild.146131/post-1853541
Both of the rear z55 part #’s will work. May as well as use the higher part # because it’s the latest version. No coil over set up offered unless you go to overseas made junk or off road capable which will give u a bounce house.
All rear z55 are air adjustable for ride height via the compressor controlled via height sensors in the suspension. The front is active like the rear but not height adjustable.
Again you have all the same parts as my 09 Escalade except yours has z55 strut inserts. Use that link above to order all the parts from R/A attached to your strut. Don’t forget the 5% off coupon for R\A
