Ok everyone.. I'm totally new to RAP4, fairly new to paintballing.. This is whats on the way

the t68 gen7 extreme sniper
http://www.choicepaintballguns.com/product/P00346With it, i have ordered an 18'' rifled barrel (upgrade option from the site)
splitfire dual feed adapter, an extra magazine, and the 3000psi butt stock air tank.
I also have the tiberius SOCOM edition t8.1 pistol for a side arm. I will be playing woodsball, got the ghillie suit and everything.. totally addicted to this sport,
Im basically hoping for any advice from anyone who has this gun(the rap4). what are the best paintballs for it, (reasonably priced of course) and any other helpful tips that you all may have. I may be thinking that the 18 inch rifled barrel may be a bit too much, and I've read TONS of conflicting information regarding rifling etc. So ANY feedback i hear will be greatly appreciated!
Thanks guys!
Nick