Shameless plug, but here it is anyway:
There is a lot to consider, but the biggest IMO is the power required. Most non-FI bikes have alternators around 60 - 80 watts, which is enough to power the head & tail lights... and thats about it. A higher-pressure fuel pump will easily draw 60+ watts, injectors & coils will be another 40ish, then you still have all the lights & need to charge the battery, so you're looking at needing to at least double the capacity. Modern FI bikes have 300+ watt alternators, for reference (more for touring bikes).
Then, as mentioned, there's the fuel system, where you'll need to package the pump either in the tank or externally, but either way you're flowing much more fuel than most of the petcocks could manage, especially considering that any external fuel pumps you find will have much, much more flow than you'll need. That Walbro pump (255lph) can flow enough fuel to supply a 350 hp car running rich, all that extra flow for a 50hp bike will just be sucking more current (for this one, maybe 120watts), requiring you to have a much beefier charging system. Walbro makes a 150 lph pump that I'm using, but even that is way oversized. (I also have one of the 255lph pumps in my project car, and it's been problem-free for 30k miles & 5+ years for what its worth)
Also, I hope you like wiring, cause you'll need to create a harness out of scratch for all the additional sensors & controls of the MS system. I got one from a wrecked CBR F4i since I was using a number of other components from it, so all the connectors would be there (which can be some of the more difficult parts to find).
Its a really fun project, but make sure that you know what you're getting into, and have the ability to do some fabrication work when it's needed. Good luck!