I'm with Geofkaye here. Scary tho. I used to prefer the older allegedly less complicated stuff. But, the new engine management is the only way to go. At least that's how I fell about small block Chev's. It's just so much better than an old carburated engine. In all ways. I don't know anything about truck motors. But, I have two friends that are heavy truck mechanics. They will tell you the newer computer managed engines are much better in almost every way than an older engine. Sure, you might have to spend a few bucks for some diagnostics if you do get a code. But, it would likely be cheaper than hunting down a problem with an older engine that won't tell you what it's mad about. I would also hazard a bet that the newer the engine the better it's made. Generally speaking anyhow. I'd stop at some truck repair places when the guys (mechanics that is) are sitting outside on the wall during lunch break. Pick their brains about your concerns. They'll be the best resource I would bet. Real world experience, no substitute for that.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio