Need some help with Fine Molds X-Wing Fighter

Question 2:

What are the best references (books) with full-color photos or paintings of the X-wing?

I have a great (paperback) book called "Star Wars technical journal" by Shane Johnson which features three full color pictures of an X-Wing from the first movies. Very good reference as you can see top, bottom and rear of the model. When I looked at the first three movies to do some research on my Millennium Falcon, I discovered that Lucas has used considerable artistic license when it comes to consistence between the models used. Try figuring out how many landing gears it has, for instance. In some shots 3, but on Bespin it's 5?! Go figure. What I'm getting at is, don't be too hard on yourself when it comes to accuracy. Having said that, the X-wing in my book looks a lot like the model in your link there.

To the questions: the engine exhausts are a color between a gunmetal and a medium grey. No real metal shine to them, and matte. One shade lighter than on a real world Viper tail (exterior). The edges look to be drybrushed with a lighter grey (approx. fuselage color). As regards the washing technique, your plan sounds spot on. Have fun on your X-Wing.

Just a couple of ref pics here to help ya.
http://www.starshipmodeler.com/starwars/smith_sw.htm

You definitly want to seal the decals before you apply your wash but as to whether it would work better on a gloss or matt finish, I have no idea.

Well, wouldn't a sooty type of wash look better being applied to a matte finish, since it'll hold onto the paint, instead of sliding around making it look streaky? Just my $.02

The problem with washing a matte coated model is you get fuzz where the ink or paint bleeds out. WIth a gloss coat the was tends to go where you want it and is easier to clean up.

And yes, wash over the decals. Then matte coat it and do some pastels for the sooty parts.

I don't do a lot of Sci-Fi but I know how to wash an aircraft and the basic technique is pretty simple:

1. Paint base colors
2. Gloss coat (Future Floor polish or similar)
3. Decal.
4. Gloss coat to seal and protect decals
5. Wash (oils, ink, whatever)
6. Flat coat (Pollyscale Clear Flat for me)
7. Apply pastel chalks (soot, scoring, dust etc...)
8. Nearly there
9. Final flat coat to seal your model

I hope this helps
Darren