I may have only been playing for a year, but I picked up a lot of things in that year. The marker i have now is an autococker that is upgraded to the max with a 14 inch dye boomstick. I'm saving up money now to get some nitrogen tanks.
None. Don't even buy this marker (seriously)
Well.....it does have nice grips, and it comes with an expansion chamber but that's it.
Lots of stuff. This was my first gun and it sucked. ok, ok, first of all: the little vertical feed off to the side may seem pretty cool at first, but it sucks! i chopped a ball every other shot (seriously) because the feed was so horrible. And it costs way too much. The gun probably wouldn't of been so bad if the feed was standard feed.
I would strongly recommend buying a Tippman. Tippman's are reliable and will outlast any rebel that comes along the way. Either a Custom 98 or a Pro/Carbine. Oh ya, and does anyone else agree with me that 32 Degrees needs to make some markers with GOOD feeds? Tippmans come with a built in feed and you can still aim without it being in your way.