M-unit is pretty easy to do on a K bike(any bike really). It will allow you to ditch everything in your relay/fuse box except the starter relay, the fan relay and fuel pump relay. There is a wiring diagram for a k1100 on the forums here, and I can probably get hold of one for the 2 valve bikes too if you want it.
For the airbox thing, you'll need an adapter for the mas airflow sensor. Just google k100 cone filter adapter and you'll find some options. Its not possible to delete the mass airflow sensor and still use the stock jeteonic ECU. If you want to eliminate it, you'll need to do a lot of work and use a megasquirt or arduino. Not worth the effort tho, just keep the stock jetronic ecu and get an adapter for the MAF unit, there are several options out there. Heck you can probably find a 3d file and 3d print one.
THe airbox thing is irrelevant to the m.unit. The only thing the m.unit does is replace a bunch of relays and fuses....it wont control your ignition system.
There are other lower cost options that do the same thing an m.unit does, but IDK if any are bluetooth. The m.unit blue has bluetooth, which gives you setup menus on your phone screen, instead of the analog menu on the normal m.unit. There are some other nice functions on the blue model. m.unit basic will also work, but its not as easy to navigate menus.
m.unit is a standard for a reason, they just work.
edit: I just posted the m.unit wiring diagram for the 2 valve k bikes in the electrical diagrams/schematics forum on the main page. Make sure you get the 2 valve one...it says for k75, but will work on 2 valve k100 the same way.
