One problem I ran into was the drive shaft being to short.
I had the stock Halo Too 4 fingered drive plate with a Halo Too rip drive.
The Magna kit has a longer drive shaft and a screw with a wider head allowing for a successful drive kit upgrade.
You can see the drive shaft in the photo Simon posted earlier.
The width of the correct screw head is apparent in the photo pote posted.
S4 drive kit is definitely sturdier where the spring tabs contact.
Drive shaft comparison:
Halo Too rip drive kit.
Halo B rip drive kit.