Up Rev is the company that offer the ECU tuning for the Titan.
There's a few ways to go about it.
1st, Custom tune, they strap your Titan to a dyno and tune it, adjust timing, A/F, remap DBW, ect. (Great if you're near them and can get to there location in Austin, TX)
2nd, Mail in tune, send your ECU to them, they will flash your ECU with a "generic" tune MAP (one that closely match your mods). (Cheapest route to go, truck will be down while ECU is shipped to them)
3rd, Osiris software, they send you all the software you need, with a MAP for you Titan, flash it to your ECU yourself. The Osiris include the Cipher data logging software to let you monitor your truck ECU, take that data, send it back to them, they will fine tune your MAP and you flash it again. (Good for those not close but don't want your truck down while ECU is sent off)
www.uprev.com