Brake problems, Rear wheel hop

[TroyZ28]

It feels like my rear wheels are severely hopping when I do a hard brake from like 80-5MPH on semi-uneaven pavement. I typically dont push in the clutch during braking if that has something to do with it. I only push in the clutch if I come to a complete stop or need to switch gears.

This seems to be a new thing. Its caught be by surprise a couple of times.

I have the following mods on a 2002 Z28 M6 60,000 Miles:
KYB AGX adjustable shocks with Ground Control adjustable coil overs with Eibach springs. I believe the spring rates are 500 in front and 175 in the rear.
BMR SFC's
Relocation Brackets
Pan Hard Adjustable Rod
Emergency Brake tightened by dealship prior to suspension mods.

Please tell me what you would do. Any additional suspension mods I need like a torque arm? I am going to a brake shop soon because I dont feel things are right.

So far I been told to buy A good aftermarket torque arm can help 75% of the issue (spohn etc), LCA's, and replace stock rotors and pads with aftermarket ones.

[joe ws6]

if i dont push in the clutch at high rpm and brake a littel hard i will get wheel hop also. Though if i do push the clutch, i can brake as hard as i want which i often do. I guess its from the drive line doing some of the braking.