I ordered these panniers from MTD Luggage a while back now. I am very impressed with the quality of them.
The right side is full size and the left has a cut-out for the exhaust. They are very well put together and seem to be completely watertight. They mount using the standard GS Adventure racks and the hockey puck mounts at the top. They are the same width as the handlebars which gives a good guide for those tight spaces.