Just a brand new owner of one of these. Very nice I must say. Very solid feel and handling. Shoots strong, and good ROF. Lipo-ready. Haven't yet taken the mechbox out, but the only upgrades I plan on doing is checking the shimming, put in a sorbo pad, and a tightbore barrel. Everything else in the mechbox is all metal: gears, piston teeth, cylinder/piston heads, hopup unit, gear bearings, etc. From others who have the CA pro-line version of this gun, they say nothing but good about it.
Tinted upper receiver looks quite black when you have it in your hand. Two light coats of black krylon should do it.
I'll see if I can get a chance to do a full review on it next week.