I understand your concern, but I really don't see how trimming down the trigger guard a bit could lead to some catastrophic failure.
Actually, I don't either. That being said, consider one thing - This is a polymer frame. The shock and stress of firing the weapon is borne and distributed
throughout the frame. Not being a gunsmith or engineer, I don't know
for sure if trimming the trigger guard would have adverse effects or not. All I'm saying is, be very very careful. A frame failure not only costs a lot of money to replace the frame, it can possibly cost you or a bystander a great deal more. Maybe I'm just being a nervous-nelly, but I witnessed a frame failure on a 1911 in the service. The unfortunate man did survive, but it cost him the vision of one eye and hearing in one ear.
It's fun to "gadgetize" and God knows I enjoy it also. Just make absolutely certain you don't sacrifice safety for "cool". Good luck whichever way you go!