I want to upgrade the barrell on my first paintball gun. It's a Spyder
Fenix. Any suggestions on barrell upgrade??

My advice is this:
Worry less about brand of barrel and more about paint to barrel match.
Do you generally use the same paint every time you play? If so, you might want
to figure out the bore size of that paint.

If you use a few different kinds you might want to consider a barrel system,
instead of a single barrel. Something like the freak junior for example would
let you size the barrel to various sizes of paint and essentially elimintate
the need for any other barrels (At this point, I have a freak system and have
more paintball guns than barrels as a result).

Mitch