Let's put it this way, if you're on a budget, then your better suited getting one set of high quality and versatile gear. You can design a load-out quite easily that'll work well for CQB and outdoor play. Having lots of guns and gear is great, but having better is better.
For example, barrel length has little effect on performance, if of course your hip-up and nozzle grouping is adequate. Then it's a matter of a quality barrel and balancing your guns sheer power with high quality BBs. Other upgrades can come later. Once the BB stabilizes in the barrel, more length does nothing, so it makes sense to have your gun no longer than necessary. Although I love the look of long guns I run an M4 CQB/CQC rifle. I could throw a standard M4 barrel on, but it's not likely going to increase performance, so I run a CQB rifle indoors and/or outdoors.
Gear should be fitted to you and to encompass your needs, looking cool should be a tertiary goal. Besides, most modern gear is pretty cool and there are always ways to make it your own.
Things like eyewear, boots, gloves, sling, etc, are easy to buy with a universal functionality in mind. Once you get into BDUs and rigs, then you need to put a little more thought in it. For BDUs I only recommend the modern type of dry-wick integrated up and integrated knee pad lower. They are easy to find, low end real steel are on price par with replica, or nearly, and they are the most versatile. They work well in hot weather and in CQB. If you get cold, just throw and extra layer on and you don't have knee pad straps digging into the back of your joints.
For things like a plate carrier and battle belt there are many, many options. Modern, fast attack plate carriers are very light, very comfortable and very modular. Not only are they the best option for proper weight dispersal, but they can carry up to 48 hours worth of gear nicely, and obviously, can be easily rigged down for CQB, where you're still loaded with water and magazines, plus whatever you need. Same goes for battle belts.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē