Not a lawyer, but I would be leery of making any modifications that the plaintiff attorney might find as as evidence of your wrong-doing. Even if you were not prosecuted - or cleared - in crimical court, you could still be sued in civil court (wrongful death, etc.).
Say you modified the DA trigger from 12lbs to 5lbs. They could argue that even though your shooting the other guy would have been justifiable self defense, your handgun discharge was "accidental" because you lightened the trigger too much. In fact, your gun went off not because your conscious pull of the trigger to execute an act of self-denfense, but rather an unintentional discharge because of a "malfunction" of the firearm.
No guarantee these arguments would prevail in a court of law, but why expose yourself to the possibilities?
Now if you just change the grips - unless it is some gross alteration - you are most likely okay. The plaintiff's attorneys may still try, but there is not a whole of meat for them to sink their teeth into.