I didn't think Jax Trust gear was enchantable. (CHECKING) The Bat (Jax Trust Lance) is not enchantable so I you can save your gold :-) The Bat
The real question is, do you have 19 friends or can you get into KNXX? If you can do this, get your Mayhem gear for your lancer. It's easier to MW and it's slightly better than Regents and it's BoP. From past discussions the Jax Trust gear is equivalent of +7~+8 agnitor. You can complete all dungeons as a lancer in this gear (in my opinion), just not as easily. Gate Keeper
Honestly I don't know what to say about which dungeons to run with lag. If my ping is ~150+ I get crabby and can notice skills not going off on time and can make proper adjustments. At about ~250+ ping I usually log off and don't play because i'm having 1/2 second delays or more on getting blocks up.
I hope this helps.