The only color that is exclusive to the Adrenalin package is "Colorado Red" and that's what we've all seen in the official pictures. Black, Silver, and White are the other colors available for the Adrenalin and they are already offered for the current Sport Trac. Still, I'd like to see the actual Adrenalin model in these other colors as well. Actually, somebody did a photoshop in another thread.
As for the mileage, your mileage may drop a little over your gen1. But as for the mileage between gen2 V6 and V8, I've read that it's negligible. So if you can afford it, just get the V8. Also, I'd be suprised (well, maybe not surprised so much as disappointed) if Ford doesn't put one of their touted "EcoBoost" or "Twin Force" engines in it in the future.