stupid question. is there a way to remove fuel injection and go to a carberator?

[NO717]

LPG conversions for the m42 is prevalent here in Germany. So it's doable.

[bme30]

I looked into this a while back when i was researching for my itb project..
Get webber dcoe side mount carbs 40 or 42mm
Replace your fuel pump to a low pressure pump

Now for the ignition timing 2 ways...
1. Buy a msd ignition timing kit for the distributorless set up
Or
2. Maybe get the software from bmw connect to adjust the timing and disable the FI features.  

I found it easier and cheaper to keep it injection

Hope that helped

[Gruelius]

should do a pushrod conversion while you are at it