Dude.. that plate is seriously messing with your anti squat. Or maybe its the angle of the photo, but, It actually looks like you have pro squat... NASTY!!!
I'd strongly advise you replace the chassis and get shot of that plate. Either that or as a desperate measure put a similar thickness plate under the front bar, whilst not ideal, as you will raise the roll centre considerably. This option is far more preferable than pro squat though.
Another little tip, I used titanium screws in the back of my S4, they seem to wear less than steel ones and so protect that rear lip better.