i second what gregrob says. the 6.0 IC is a direct drop in, easy swap too. definitely go with a BB type turbo, cant go wrongDave, I would be looking at big oil and a turbo. A turbo will probably help with egt's quite a bit and make it fun to drive. (ball bearing version)
Big oil will make a huge difference in throttle response, driveability and towing. It's awesome.
You could do a 6.0 intercooler (33% larger) unless you're going for some serious fuel.