Anything that fits in the standard feed-neck. So no A5 cyclone feed tops.
the smart parts ion is by far a better gun. the vibe is a waste of money. the ion is a little more expensive but you won't go wrong with it.
There are a few places where someone could purchase a Smart Parts Ion paintball gun. A store like Sears, and websites such as trademygun, and ultimatepaintball, all sell Smart Parts Ion paintball guns.
A used Smart parts Ion can be sold for around 100-200 dollars depending on condition and what your willing to sell with it.
The Smart Parts Ion is a fantastic gun, in the sense it can be upgraded easily and it is not the most expensive gun. There are not nearly as many upgrades for the Piranha.
Online, or at any place that trades or buys markers.
a new feed neck or a drop forward
This bolt is an aftermarket accessory for most smart parts gun. This bolt lowers the operating pressure of the gun as well as helps the accuracy. The bolt fits any ion, vibe, SP-1, EOS, and Ion XE
An Ion is short for the marker, the smart parts "ION." It is an electro-pneumatic marker with impulse barrel threads, ion feedneck threads, and reverse threaded regulator threads. The classic ion cost about $200, where the new ION XE costs about $220.
Smart Parts (Now GoG) made mid level electronic guns. The Ion series (now eNMEy) was a popular, relatively inexpensive speed ball marker with huge customization and potential for high fire rates. The SP1 was an Ion with a more tactical looking rugged exterior and good customization for woodsball. Both series were relatively cheap for high fire rates but lower reliability.
The Ion is considered higher end with a different bolt style, body, board, feedneck, and barrel. The Ion is also much better on air and faster. Though the aftermarket upgrades are very similar.
The EOS is basically an Ion with a different body. The bolts are the same as well as the internals. The common joke with EOS's is that "It's an Ion on steroids". before sp went under they really only made 3 markers, the shocker, the impulse and the ion, everything else was a ion clone
I would recommend the SLG because with the smart parts ion u have too upgrade it a lot to make it a great gun, with the slg itz fine right out of the box it comes with a better board an asa already on the gun and a clamping feedneck.