craaap. What kind of problems do they cause? How much do the stock remotes cost? What would I have to do to remove the aftermarket stuff and put in the old stuff?
In Basics:
keyless entry works by frequencies. BMW has it's frequency; vis-a-vis the frequency that the aftermaket item uses.
Consider this: even if it is plug-n-play and you can successfully get teh aftermarket unit to operate. You are in effect operating 1 system with 2 separate frequencies. If you are lucky, It might work for a period of time.... BUT, it also throws your system in a (what we call) a 'loop". Over time the system will be confused as to what frequency to recognize and then, the system goes "GAGAGAGAGA....." , and, problems begin.
Then, electronically: whenever u introduce aftermarket stuff in the car(including plug-n-play stuff); you are in effect disrupting the balance of the original system. Static and kinetic charges are introduced... that inteferes with the way electronic components perform, and these in time contribute to the deterioration of 1 part or another in a system. That translates to.....
Breakdown!
To answer ur Q: re-stock remotes
Bring your VIN & proof of ownership to a BMW dealer. They can decode whether your car has remote + anti-theft OR remote entry only(these are 2 separate items depending on year and model).
Then you can go from there

Parts of course need not be brand new. U can source from eBay or recycle shops...
