I have an 03 A6, which until about a year ago, I cleaned throughly and regularly. I started grad school and ever since she's been lucky to take a ride through the quick wash at the gas station. I've browsed a couple pages in this forum and picked up some good tips, but there are 3 areas where I have some specific questions/concerns:

Interior (black lthr)- So the one thing I never did regularly was condition/clean the leather. The other day, I reached over to the pax side and realized how stiff (almost plastic-like) the leather had become. There are no cracks etc, but I want to approach this properly. Is it okay to go at it in one sitting with some cleaner/conditioner, or should I do it in multiple steps, over time? Which products work the best? In any case, could someone point me to a detailed guide on how to bring it back properly?

Dashboard cover- Last winter, I noticed the edge of the dashboard cover on the windshield side is curling up. Over the last year, its curled up across the width. You wouldn't notice it unless you were looking for it specifically, but it's definitely there. Is there anything I can do to fix it/stop it/slow it?

Black Plastic Trim- I cannot stand the look of plastic trim that has oxidized and turned gray. The grill and side mirror mounts on the door have done just this. Because it drives me nuts, I do use Mother's Back to Black occasionally, but I find that it simply soaks in and turns gray again within a week or so. Anyone got a better solution in mind?

Thanks folks