Which ones did you go with? When I went to do mine I just didnt think the ones being offered looked beefy enough. So I made my own and they really stiffened up my car. I did not consider ground clearance when I designed them . They are made from 1.5"x2.5" 1/8" wall rectangular tubing. They are welded from the bottom of the rear sub frame to the bottom of the front sub frame. I figured that as the rear sub frame tried to twist up that those big bars would then lift up on the front sub frame. I have still managed to warp my B-pillars even with these suckers in there . I am launching good though.
They are Kenny Brown SFC's. We'll see if they make any difference this weekend. I don't think I'm launching hard enough to have any problems yet. These are installed for future power!