@Cornbread: The Needler is indeed on of the new RB-Mod weapons and is very powerful. It is very hard to win against an alien equipped with it, BUT it is possible, just look at Lurkers way to deal with those guys: Lure them around a corner, use cover and kill them at close range (okok a bit simplified).
You will maybe ask: "Why is a powerful weapon like this in the early missions?" The answer is i couldn't make it appear later. I made a poll about the aliens carrying the new weapons and most people voted for Yes.
Try to see it that way: It's the price you have to pay for getting the improved RBmod-armours and -weapons later in the game
which the aliens DON'T have then