Adding more to what pig said,
Elite:Elite sets or (E) Drops are only available for members (only members can wear them), though any normal player can get an "(E)" part.
The difference of this part is just the color, and the stats are "+5" of the set you're wearing, The (E) Sets available are from lvl 1-107, DarkSurge (E)(Lv. 196) would be the next one after these, and DarkSurge (E) is bought with real life money. You only get these drops from the "elite" sector of each map. Theres also "Elite transes", though, these are bought from Admins. Specific Lvls you get these armors: 17,31,48,61,76,86,94,100,104,115,121,126, for a higher chance, I'd suggest you get some luck in-game.
Survival:Survival armor only drops on the survival game mode which is accesed with the tag "{s}" (which it should be kinda obvious
), you get to get drops/boxes when you reach "Tier 1", these "Tiers" are reached by killing a certain number of mobs, which means for "Tier 2"/"Tier 3", you'll need more kills than the ones for "Tier 1". As for a example: Tier 1 is reached at 10 kills, Tier 2 is reached at 20 kills, Tier 3 is reached at 30 kills.
If you get to a certain "Tier" doesn't mean the next box would be that "Tier", even if you reached Tier 3, you can still get boxes with "Tier 1" Drops. Each level has its own "Set", each one is different. Tiers add more "details" to the armor, and increase the stats. Available for non-members and members.
"+" Items:Well to start off, the maximum "+" you can get on a drop is "+5", to get a higher chance for these parts to drop, I'll recommend you a "LuckyAura" E.F. , I'll also suggest you try a higher lvl than the "+" of the armor your "hunting" for, Example: Try lvl 172 to have a higher chance of a "+5" item instead of trying lvl 161. Some of the "+5" parts aren't available on every lvl, What im trying to say is that you'll get a "+1,+2,+3" item if you're playing on a lvl lower than the armor your trying to get. "+1,+2,+3" Armors let you wear the armors on a lower level than the required one, meanwhile "+5,+6,+7" armors are only equipable if you have reached the exact level of the armor, in the case of +6 and +7 you have to be 1 lvl higher or 2 lvls higher than the requirement to wear them.The "+" box that will drop depends on both your In-game luck, and also "your luck" (What im trying to explain here is that if you have more In-Game luck doesnt mean you'll get a "+5" drop always.)
And to "increase" these "+" on your items, you can just buy a "Combination-Coupon" from the shop (6,500,000 Millions of gigas), and get 3 parts of the same "+" and combine them with the item. For an example: You need 3 +5 arms to make 1 +6 arm. How are these parts different? Well these parts have increased stats of each armor, for example: a +1 Arm gives 200+ TransGauge, meanwhile a
+2 part will give more of that stat, lets say 250+ TransGauge to your bot. These parts are available for non-members and members, the only "+" parts that arent available to non-members are armors higher than lvl 172. "Elite" levels also give you a higher chance to obtain a "+5" item.
Event Items:Well, these items (such as the ones you mentioned, walker bro, jura trans, dark meto, Halloween Set, etc.), are only obtainable from each event the Admins make, (excluding items as transes, those are bought from the admins) for example, each holiday normally has a certain item for the event.
I hope you get to understand the items more with this.