I've installed a BMS intake on my 28i and it came with everything to accommodate the upgrade including the MAF sensor. Images are available on my old thread:
https://f48.bimmerpost.com/forums/sh....php?t=1526064
I didn't notice an increase in power, but more so an increase in hearing the engine and turbo. I think the most significant difference I found was when I chipped the car to adjust the boost.