I've used Molecubond on my int. door panels and center console, and also on my mud flaps...everything turned out great. Of course, it won't help w/ blemishes in the vinyl, but it brought my faded gray faded int. back to a deep black. It didn't say anything about using a sealer or clear coat, but nothing is flaking off at all. My car is in the sun a lot (which sux when it's a black car) and the door panels seem to be fading a little already, but it's been about a year since I did it last. I didn't even bother to take the door panels off...I just used the thinest painters tarps I could find and taped everything else off. I removed the center console and mud flaps to paint though. It dries pretty quick, so you won't be w/out anything for a day or over night or anything...
You might also want to check out some stuff that JCWhitney offers...I haven't looked into it, but it looks like there's a clear coat or sealer that goes with it. There's a link to JCWhitney on the Shop Online page at http://www.toyotacelicas.com/shoponline.html.
Supposedly Molecubond penetrates and bonds to the molecules of whatever you're painting, so maybe that's why you don't need the clear coat or sealer, which probably makes it better.
I've contacted Molecubond when I first used it and they told me something about having OEM contracts w/ most auto makers besides Toyota & they're working on that...now that I think about it, I don't know why'd they need to use Molecubond on new cars....maybe I'm just confused
Anyhow, let us know how everything comes out, whichever way you decide to go