You are going to hear the die hards on both sides of this issue. I am personnaly a fan of subframe connectors coming from the SN-95 world where they are a must. Yes the S-197 are way stiffer than than the SN-95s. But I still noticed some creeks and stuff in my '12 riding around the rough streets of SD. I installed a set of BMR subframe connectors and the car feels more planted for sure but I can tell a big difference in ride quality. The car feels real stuff now. Where before when the front tire went over something I didn't notice the body reacting. Now if I go over something with the front tire it feels like the whole ride of the car lifts up because there was flex there before.All the small noises I heard before are gone but I also feel some of the ride quality is gone. For a daily driver I think it's best to leave them off. If you aur like me and only drive you car every couple months like me or take your car to the strip or doing some twisties I would recommend installing them. They don't weight hardly anything so it's not going to hurt if you do.
The nice thing about the BMR connectors is that they provide a "jacking rail" down the whole side of the car. I also like the way the tie into the lower control arm bracket.
As a glass roof car that I race, I followed my gut and excellent experience with pervious SFCs.
I went with Stifflers bracing system and highly recommend it. Makes even a DD feel more solid, plus easy to jack car now. Minor weight gain only negative, so go for it! I welded on.
-J