Honestly unless you guys are willing to use masks with goggles, don't use anything stronger then the cheap spring ones.
The gas blow backs and electric can be very dangerous without the proper safety equipment and safety measures. These guns are not some little toy which you can go out and have "wars" with your friends. Not only do they shoot hard, but they shoot very fast. I have a tokyo marui p90 and that thing shoots fast, if someone is not wearing the proper safety equipment they can get seriously injured very easily.
Also these guns are generally good replicas of the real guns, if you go outside with these airsoft guns, you might get into trouble with the law, as in shot by the cops.
You have to also realize that the electric and gas blowbacks are a bit expensive, the gas are about 100+ and the aeg are around 200+. The metal ones of course cost more.
I recommend the spring because as you just stated you DO sound like a immature kid and I don't want immature kids playing airsoft and giving a bad name to this sport.