I too own a black x-fire. What I recommend is if at all possible, viewing your paints surface under flourescent lights (in a garage), or under some super bright lights like at the mall, if these aren't available to you, pick a good sunny day and examine your vehicle from all angles to get an idea of how good or bad the paints surface really is. You have to be the one to decide if you're satisfied with it. As far as using 3M Hand Glaze as a wax, although it does give you some protection from the sun etc, it is just a "filler" glaze designed to "fill in" the imperfections in the paint, ie: swirls, scuffs etc., not act as a wax. What I did with mine was washed it really well and dried it by hand, then parked in a cool shady area for the 3M.
The stuff is very creamy and non abrasive, work in small sections at a time. The bottle suggests working in an area small enough to wipe off before it has a chance to dry, but don't worry, even if it does dry it will NOT damage your paint, just makes it a little harder to get off which means more elbow grease and time. I would use the 3M a couple times at least to get the desired "wet shine" look you're after. As I had said in earlier forum posts my x-fire was swirled by a buffer.(Never use a buffer on a x-fire, the paint is too soft, look at some other forums and you'll see others agree with me) Anyway, I only used the 3M one time so far and man what a difference! I love it and will continue to use it. Now back to your question, as I said I would use the 3M until ur satisfied, once you are then use a good wax (by hand, I know it sucks by hand but it's your baby right!? lol) Hope this has helped. Please let me know what you think after you try it out. Happy motorin'!