For anyone looking to refurb or replace a rear subframe on their 2002-2005 Audi A4 B6.
I sanded off old rust or rough spots and put around 6 thin coats of rust proof paint. It makes a hard shell that's supposed to be rust free, so it should be good for awhile. The paint looks terrible because the coats were thin and runny, but it feels like a hard shell.
Come grab it, swap in your subframe bushings of choice, and have it ready to go before pulling off your old one.
bushings on it are from a 2004 Ultrasport, so a bit stiffer than the 'normal' / standard suspension.