lots of ppl ask what the difference is between piranhas. all the 2k4 models are based on the same design some just have more on them and modifications than others. since there is lots of differences between the old piranhas and no one really sees much of them any more ill just talk about the 2k4's and the new 05's. the 05's so far look like and operate just like the 05's so i will talk about them as one. ill start with the mechs.
the black maxx- the black maxx is a 2002 model and it is still made today and is one of PMI's best sellers. it is made of polymer and operates differently. it is not a piranha but it is a PMI marker. they tend to sell at 25-40 bucks. it is a basic paintball marker and can not be upgraded other than the barrel. it is a very nice beginner marker and is just as good as any other stock mech.
the next 3 markers are available in mech or e force frame. the eforce frame allows you to shoot faster with a lighter pull. you can also pick for semi, auto, and burst. these boards are capped at 13bps. (for moreinfo check the link at the bottom)
the R6- the r6 (mech) performs much like the blackmaxx but is a piranha with a rear cocking system and is made out of aluminum with teflon coating internals. it does not have a inline reg or gas threw so it has no forgrip. it does have an asa witch is screwed to the bottom of the trigger frame.it also has a volumizer. sadly you can not add a regulater or gasthrew to this marker without buying an adaptor.
the GTI- much like the R6 but has a gas threw grip stock (witch acts as a forgrip). this will also allow you to add a reg.
the SRT- this marker is much like the GTI but has a removable feedneck and a flush cocking system. the velocity can be adjusted without an allen wrench and out on the field. it also has a slightly different milling.
the EXT- mush like the srt but has a reg stock(not a gas threw), a ram air chamber, better stock barrel (12in.),and a drop. this only comes in e force.
the EVO- PMI's flagship marker. it is like the EXT but it has a milling that is different from the r6/gti/ and the srt/ext. it has the same barrel as the ext. it has a modified e force frame. the auto and burst have been replaced with a shot counter and timer. it also has beam break eyes so your odds of chopper r reduced. with the eyes on the board is capped at 20bps.(not 13 like the stock e force frame)
for more info on these markers look