  We present a microscopical theory and experimental results concerning
resistance resonance in two tunneling coupled quantum wells with different
mobilities. The shape of the resonance appears to be sensitive to the small
angle scattering rate on remote impurities and to the electron--electron
scattering rate. This allows the extraction of scattering parameters directly
from the transport measurements. The negative resonance in a Hall coefficient
is predicted and observed for the first time.
