Just keep it basic man. No after market high horse injectors, toss on a powermaxx turbo, conservative tunes, etc.
With towing you want reliability also, so IMO, things like fuel pumps and injectors should be left to factory. Nothing could possibly frustrate you more than being on the side of the road thanks to one of dem der fancy high dollar fuel pumps... I've seen it time and time again with those things.
Included in basics are of course EGR delete and the head studs. You've been here before so this should be of no surprise. Factory gaskets, a good prep job, and a good fire ringed head, preferably built off a OEM casting not a cheap Chinese one. The only issue I and other shops that I keep in my network have issues with is keeping oil temp in spec with a heavy load. This is where they have actually recommend the external oil cooler kits, mainly from BPD. I myself have installed 3 of these kits, but without having gone the distance I cannot say how well they perform, but in theory it seems great. You just have to watch the routing of the hoses. I have had one break down on the highway due to a rub through on an oil feed line. Whoever installed it, clearly was not routing the lines properly.
The drive line in these are damn near trouble free. I have put many tuners in very high mileage trucks with factory Trans and they still take the beating
