Welcome to the forum Mina!
Here is the stock Aeron B96 with the original sights and compensator:
Here it is modded:
The dot sights work by reflecting the image of a small dot of light projected from the back end of the sight. A semi-transparent lens is used to reflect the image of the dot so you can see both the target and the dot. The lens is curved in such a way that the dot is stationary relative to the gun regardless of the movement of you eye relative to the gun.
The thick black barrel is a custom fitted shroud or LDC.
It will not affect accuracy if constructed properly.
As long as the pellets fit snug inside the magazine and not protruding, you will not have any feeding problems. So any shape pellet head will work, as long as it is not too loose or too long. Most common pellets will work.
......between ETA,airgunfun, and sniper ... my list of guns to get has grown so big ...it no longer fits neatly in my wallet 
.......Oh what is a guy to do?....Well I figured it out. 
...I ask the guy in the funny red suit to bring me a PDA 
.....ETA thats another great gun you've got there 
...
