Most of the people who ask for advice on this site do not listen, but here goes.
a: There are a few people who use them, most people choose not to. (smart ones)
b: Removing it is the best option
c: yes, as long as the fuel system is in order
d: no
Get rid of it. buy a power FC, i have one for sale with $1250 with hand controller. and then get it tuned and the issue will be fixed.