Thought I'd just add my experience in for those that might be interested...
Dropped the exhaust off the rear hangers and supported with an engine lift so that I could get good enough access to the top of the rear box.
Prepared the surface by cleaning with wire wool and a degreaser and then scuffed the metal slightly with some Emery paper.
Masked and taped around the area and just used a big piece of card to protect any other areas as I sprayed.
Did one light coat first, allowed to touch dry and then did a heavier coat and ran the engine to dry it, followed by an hours drive home on the motorway.
Really pleased with the finish - super cheap improvement!!
