I prefer Stock II because sights returns better than with Stock III. Make sure you're getting "new" Stock II - it's a different gun - see the New vs. Old thread recently here for details. Improved serrations and I need no grip tape anymore.
I believe, Xtreme line is a good value. 4 mags, pads, aluminum grips, FO front sight, factory polish, etc. I only change to 2.5mm wide front sight out of habit and install shock buffer. Coming from Glock, you'll probably find 3mm sight comfortable. I skip the accessories, then dry fire, live fire, and it's fine in a week.