Honestly I use both TokenMaster’s Pro Launcher and BimmerUtility, either is fine. You can probably find free versions of it if you look around, but for me it wasn’t worth the hassle. I’d probably lean more towards BU just because it’s a quicker method of getting it, TokenMaster sometimes takes a while to respond.
And no reservations at all about it, I did several retrofits in my 530e as well without issue. The 48v though is for the mild hybrid. For the plug in hybrids, there is a disconnect for the high voltage system located towards the top right side of that same area where the second battery is located. You can see a picture of what it looks like here:
https://f15.bimmerpost.com/forums/at...1&d=1612913881
I always disconnect that first, then the smaller battery below it, and lastly the larger main battery, and when reconnecting them I go large, small, then hybrid. You will need to use a small flathead screwdriver or similar tool to pull out the tab on the right side of the hybrid connector to allow you to push it back in.