I don't want to make you feel bad, but my noise level is between S1 to S3.
Are you sure you have it mounted on/in a Landcruiser? :-)
(without the PRE amp. When I click in the pre amp (+12dB) the floor noise level go to 4 or 5.
I just got in a 1"x0.46" x 100 feet tinned copper strap. So I will be doing some more bonding to appease the RF Gods. :-)