K, so.. Jax is freakin OP bro. I looked at some of the dominion guides out for Jax, and, trust me, they are doin' it wrong. ;) You might see some things in the guide that are counter intuitive, but trust me.. this is one beast build. Mid to late game with this build, It's very rare that I can't take out 2 or 3 enemy champs single handedly, while tower diving. Lol, yeah. The only item I'd really say is interchangeable is the Quicksilver Sash.. Obviously that item is for when you're being CC'd (this is the only way I die, usually.) Your last item (if you ever get a dominion game that lasts this long) depends on the situation: Dying to CC? Get that Quicksilver sash. Melting everyone's face? Melt them harder with Guinsoo's Rageblade. Killing everyone quickly but dying to 2v1 or 3v1's? Get some HP, or resist, whatever you need.