I will b changing my brembo pads and have question. Do apply the antisqueal compound between the shim and pad, on rear of shim, or both?

 

if you have the shims you really shouldn't need the compound since that's what the shims are for.

...I have brembos, shims, no compound, and no brake noise at all.

 

In my opinion you should still use anit-squeal even if using shims. Use it between the back of the pad and the inside of the shim. Using it on the outside of the shim (the side that contacts the piston) can be done and will not harm anything if used sparingly, but I think that's an overkill. I would only do that if I had squealing issues that couldn't be resolved through other means.