Differences MMU3 Upgrade Kit Mk4 to MK4s  

Differences MMU3 Upgrade Kit Mk4 to MK4s

Hello,
i'm stuck with a question (and i hope someone can answer it)

Tldr: What is the difference in the MMU2s to MMU3 Upgrade Kit for the MK4 and the MK4S version?

The reason i'm asking:
I have a MK4 (no S) and with it, i've ordered a MMU2s to MMU3 Kit (because i found an unassembled MMU2s for really cheap) for the MK4. (MK4s is unreleased at the time) Wanting to get used to the MK4 first, the MMU was not installed at first and waited in the box.
Fast forward a bit, many months gone by, printer working just fine.
Then, the MK4s is introduced. As it happens, at the same time i have the possibility to acquire a new Printer for work. Naturally, i order a MK4s for work and i'm just amazed by the better cooling and such. So i order a MK4 to MK4s Kit for myself.

So, at home, i have now:

• Mk4 Printer working
• MK4 to MK4s Kit waiting to be assembled
• MMU2s Parts
• MMU2s to MMU3 Upgrade for MK4 (not MK4s)
• Printed MMU3 parts

Now, i'm planing to assemble all the backlog the next days. I'm now facing the question, what is different between the MMU2s to MMU3 Upgrade Kit for the MK4 and the MMU2s to MMU3 Upgrade Kit for the MK4s?

Thanks for your help.