It's not the lines and rotors. And rotors don't "warp". Brake vibration is caused by uneven pad transfer.
It's related to the pads. Use some anti-squeal lube (like ATE plastilube) to lube the back side of the pads and the pad slides. Also, make sure the dust/gas slot in the pad is not caked with dust.
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R