1. Yes, they are fantastic starter guns. In fact, you could make it your primary gun. If you will be getting into speedball, I would suggest the Vibe (now GOG eNVy), the speedball version of the gun.
2. There are indeed aftermarket parts or upgrades. The blackheart board will make it have the ability to shoot up to 25bps, rather than its capped rate of 11bps. It also introduces a set of anti-chopping eyes. There are also triggers, feednecks, barrels, and so much more. But just get the necessities in my opinion.
3. Some of the pics have custom modifications, but not all. You would have to read what these people put into their markers.
4. The 9v battery is to make the gun work because its an electronic gun, not a mechanical gun like the tippmann 98 or something of the sort.
5. I would recommend ANS Gear, the gun is now under the company GOG and its title is the G1.
6. Some parts, but not all. They will be released again soon enough, now that it has made its return with GOG Paintball (redone Smart Parts)
7. Definitely reliable, very easy to work on.
8. You will need an electronic hopper. In all honesty, I would do some research. If you are looking at a Halo type hopper, take into effect it has a very thick feedneck so it will be very hard to put it in and take it out of the gun.
Good luck bro.
**Also, since its now only a $50 difference, I would suggest buying it with the blackheart board already installed. It makes a night and day difference. But also, read your manual thoroughly, and before you go play, make sure everything is working. The worst thing is to go out with a new gun and have it not work.**