Nothing really, I suppose a new board is good. The stock on the 2004 I know is only semi so if you play in some leagues that have ramping and other modes you'll need to upgrade.
Lightweight, INSANE FAST, suprisingly tight.
Destroys compitition way too easily
My coach has this gun and I had the honor of using it one practice. The thing is exactly what god would use if he played paintball. I mean the thing is out of control sweet. But now on to the review.
Accuracy- I know the stock Matchstik barrel is very accurate but my coach is a big fan of Stiffi so he got one of those to take rope throwing duties on the gun. This upgrade might have been a little unessary. The Matchstik is very accurate had is mirror-finished on the inside (duh). It is about as good as you would expect from such a quality company as Mac-Dev is. The paint goes right where the gun is pointed. No question. The stock bolt is Delrin and thus is self lubricating and the only reason for cleaning is the ocassional wipe down and a nasty gun hit. The bolt is also very, very accurate. The first game I used it with I was bunkering some new kids with such ease that I actually felt bad for them and apologized (I would totally do it again though).
Speed- Now the gun is already fast with the stock board but with my coaches Todao in it the words cannot begin to discribe the carnage that this gun leaves behind on the field. With both a new Delrin Trigger, that my coach has put countless hourse into, and the new board the gun is greased lightening. Now in this day of age speed is becoming less and less of a sweet perk and more and more like a requirment so its not like some crazy gun that goes way beyond the standards but ripping strings of around 14bps is not out of the question.
Maintenence- I really don't know about this area seeing as that I only tested the gun one day but I'll ask my coach about it and update this later.
Size & Weight- for some odd reason when I thought of a Cyborg I thought really bulky and heavy, a gun a back man would only dare use. How wrong I was. The first game with it he had me run to the fifty and It was such a pleasure to do with this light gun. With both the tank and filled hopper the gun is still lighter than many guns that boast of their weight. Switching hands is easy as pie with this gun as well. The guns size is similiar to a Timmy. Thin and tall, but not obtrusive in any way.
Efficiency- I wasn't counting or anything and I can't even get a really good estimate but I know that I never had to worry about running out of air with this gun. It was shooting 80psi though.
Overall this gun is hands down the best I've ever used. I'm buying on of my coaches (he has three!) so he can by an 06 borg. Yes I'm biased towards them but honestly can not think of one flaw that would stop me from loving them with all my paintballing heart.