It will fit both of them.
This statement is half true but half untrue. The tippmann A5 and 98 custom do indeed have different threads. But after the A5 tippmann made the X7 which has identical threads to that of an A5. Because of this a barrel with "Tippmann A5" threads, will fit on a tippmann x7, but will not fit on a tippmann 98 custom.
The Tippman X7 is better quality faster rate of fire and is just an all around better gun.
Picatinny- standard size
I believe it is a5/x7 threaded.
No, it will not fit.
Yes, and in fact there is an E-trigger addition that comes with a double trigger.
No, the mounting screws are different, it will not fit the 98. There is a 98/USarmy cyclone feed made that will fit.
The Best Tippmann is the X7 phenom. It is the only Tippmann with a spool valve, regulator and can run on batteries as well as without. The 98 is the cheapest and simply shoots and nothing more. The A5 is the 98 with a cyclone feed and slightly better internal design. The X7 (non phenom) is and A5 with more plastic- do not buy it.
No, but any drop forwards with the standard two hole fitting will work.
The X7 is an A5 with a different shell and a fake magazine. They are internally the same. The A5 costs a whole lot less. The tippmann x7 PHENOM however is far superior to the A5 in that it is spool valve and can use batteries for full auto and burst while still using mechanical semi, requiring no batteries.
Only the 98 style buttstocks, the ones with a cylinder and a hole in the front. The Tippmann a5/x7 style with the plate and two screws will not.