The things that are killing you are your 22" wheels, even if they don't weight much compared to other wheels, the bulk of the mass is much further away from the hub, which increases the rotating mass, requiring more torque to get moving.
However, for you mods with a full weight quad cab your times are about right. My '07 ran low 15s with similar mods and I wasn't into the 13s until I was running a cam/heads + nitrous. You have to remember you're trying to race with a 5900lb brick, so to get it moving you need more power.
A gear swap and smaller wheels will help with your ETs greatly, but if you really want to get faster you need to generate more power.