One of the BEST DIY's on here based on clarity, detail, and the great pics!
Only thing I would have done different is to buy just the seperate male/female pin connectors and actually crimped them on to the end of a proper length of wire instead of buying the factory pigtails with pin connector precrimped on the end - this would do away with all the twisted connections on every run of wire to get a wire with male one end/female other end. If you choose to do it this way, I would use solder on the connections before shrink tube.
Where you have to run the 2 wires piggyback from slip ring harness to shifter harness obviously you have to strip a section of insulation off straight run and twist in the piggyback wires - here I would have also used solder on the joints before shrink tubing.
I agree this is much cheaper than buying the harness & proper MFB Buttons. In my case, I have more $$ than time, so I just went with the pre-made harness and the correct MFB Buttons.
And actually, I did not buy the version of MFB Buttons that BMS states are the only ones that work. I did not want the diamond/star buttons as mine are different - bought the correct paddle shift MFB with proper logos for my car and they worked fine.
Don't know why they specify that certain version MFB? Prolly, because those are the only MFB they tested their kit with, so as a CYA, they state they are the only ones that work...