Quick one for the experts here. A friend got a 1998 Durango 5.2 in pretty nice shape and he is slowly building it into a trail rig. It has 33x10.50 BFG's now, a sweet homemade front bumper, a catback exhaust, and other real minor stuff. I've driven it offroad in a few different locations now and really like it. It runs fine but really is gutless above 3000 rpm. The engine only has about 100k miles on it but it is mostly idle hours (long story). Planning on a rebuild over the winter. In the meantime, are there any good bang for the buck performance upgrades? What is the preferred way to tune the ECU? Do they wake up well with a cam swap? I understand the heads are limited to 0.500" lift or less. I'll likely do some cleanup port work on it as well. Is it worth finding a 5.9 instead of rebuilding the 5.2?

Thanks!