Just in case someone's interested...
Epson says their durabrite ink is fade resistant so I decided to test if it's good to make decals. I printed a solid red area on standard decal paper, clearcoated and put it on a piece taken from a spare model. I also painted the area close to the decal with an enamel that matched the printed red, then sealed everything with a clearcoat and put the whole thing in a sealed transparent bag on top of my car box (so it's exposed to the sun all day). I also put inside the bag a piece of photopaper on which I had printed the same red area with my "old" (non-durabrite) printer.
I looked after one month of sun exposure and noticed that some water had leaked inside the bag: the normal ink is faded, while the durabrite one still looks like the painted red (only the acrylic clearcoat turned a bit dull because of the water).
I don't know how much of the standard ink fading is due to the sun and how much to the water, however seems the durabrite can stand both very well (for now). I think I'll put the whole thing inside a better sealed transparent box and test it for another couple of months, however for now the results seem nice.
P.S. I don't have any connection with Epson, apart from the fact that I bought their printer :)