Thank you for providing vehicle info.
The SDE product looks very similar to the initial ShockSims resistors from Xineering that I had installed on my 2015 LTZ. I now have Xineering's OBD/SS unit (
plugs right in to the OBDII port beneath the steering column - doesn't use resistors at all 4 corners).
For the rear, your B8 5100s will be fine, and also allow you to install up to 1" coil spacer for increased ride height out back. Might be necessary if you want to maintain some of the factory front rake.
I
do NOT believe that the B8 6112's will fit up front on your Denali; due to the fact that you will still need to utilize the OE shock top mount plate.
From my research, and discussions with Xineering's product engineers, the B8 6112 strut core, along with most other non-magnetic ride strut cores, are a larger diameter than the magnetic ride strut cores.
In other words, the top of the strut will NOT fit through the top mount plate to bolt.
This image is from Xineering's product engineer a few years ago that they sent me regarding this strut core mounting dilemna:
View attachment 354660
A new, full front coil assembly would be the easiest route to go regarding installation and compatibility.
Once you've deleted the magneride, you can basically install any COMPLETE front coil assembly you may choose.
Examples include: Monroe QuikStruts, Fox/King/Icon coil-over assemblies. I think Rough Country may have an offering.
ie:
Fox 2.0 Performance Coil-Over Adj (0-2"+) OE Magneride (z95) Front Coil Assembly
View attachment 354661 vs. View attachment 354662
Please don't take my comments as fact; I could be wrong about B8 6112 not being able to fit.
I would suggest doing a bit more research regarding the Bilstein B8 6112's compatibility with your front suspension plans.