Okay basically the issue with a cam is often it moves the torque curve up in the rpm range. Now a stock TC with lock up at about 1800rpm but a higher stall doesn't lock up until whatever range you get it stalled to meaning your in the power right off the bat instead of the lag that you may notice after a shift or off the line. I would say a 2600 stall is a little small but probably great for you application because the 300mm stall from Circle D will allow you to tow and give you a little more performance. The 278mm will allow for a higher stall rpm about 2800-3200 which will get you more into your power, but only allows you to tow about 4000lbs. I would recommend a trans cooler either way. Just keeps your tranny happier and lasting longer. The trucool 40k is like 180$ and very much worth it. Lots of guys like theirs a lot and it is good extra insurance. You are going to see extra wear, but with 200k its going out sooner or later and a built trans will be a great investment when the time comes. You should be okay for awhile no guarantees.

A tune from nelson is $300 which is about the going rate and he does good work also one day later down the road you could make a road trip and get a live tune in SA from him. Definitely a good choice working with him.

A good lifter to use are the LS7 lifters.