EFILive will tune it. Tuning for the 6.7 ECM is in beta so you could use it on your trucks as well. I would think that most canned tuners would work since its basically just an LB7.
As far as exhaust, I dont know what to tell you. I have no experience with the Kodiak.
Ppe will work on them. I'm not sure about any others. And efi live of course. As for exhaust, you'll have to buy a kit and modify it to work for it. There's nothing on the market for it that I'm aware of.
As for performance, they're geared really low so don't expect much. IMO the dmax shouldnt be in a medium duty truck. Its a light duty engine and does well at it. But you try and strap 30k lbs behind a 12k lb tow vehicle and ya it'll pull it. But it'll be a gutless pig and drink the fuel like mad. No amount of tuning will fix that if you ask me.