Barrels
Dude, i've got an angel and as Ben Frain said, the stock barrel is very good.
I have a Powerlyte Sceptor Kit, a Ultralyte and a Hammerhead Kit and they are all very different in their own ways.
Best bet would be to try a kit or barrel out and see how it works for you.
All you need to do is get a good paint match and you'll find most barrels are pretty good.
I prefer my Sceptor as I get more shots to an air fill and it's near enough ball on ball accurate. The build quality is second to non.
All the best,
Simon.