I've long been one of those guys that, when I replace a worn out/old OEM part, I look at it as a good opportunity to do an upgrade.
I've been rethinking this philosophy over the past few years. Here's why...
1) It seems when I make an upgrade, with aftermarket 'bigger and better' parts, unintended consequences always seem to pop up. Add a trans cooler for instance, the crappy fittings included in the kit, leak at the threads. The universal mounting albeit easy (remember those stupid zip ties thru the radiator to attach an aux trans cooler so popular some years ago?), fail latter from heat and vibration. You don't notice the behind the grill looseness, the cooler rubs the radiator support, and a leak develops.
2) When the modified part or system later fails on a long from home road trip, I can't find the parts. If it was oem, maybe no problem, but some aftermarket part that was part of a kit? No dice. And if a shop works on it, they always want to blame the aftermarket thing that has been added, as the culprit. Often it is!
3) The factory usually gets it right. Ok, I'll give you the 6.0, and it's basket of issues, but typically the factory does a nice job in R&D. Near Mojave CA is a test track, currently owned and operated by Hyundai I think, where they torture test new models in the summer heat. I'm talking about real engineered tests, with sensors, instrumentation and DAQ to record hundreds of channels of data, big budgets and PHD level analysts to later pour over that data, looking for failure modes, assessing the likelihood the manufacture will have upcoming warranty claims that effect their bottom line. The kind of thing your average guy would never think of, the kind of thing Formula 1 teams spend a big part of that $650M/yr budget on. Automotive systems are complex, we only discuss the few that fail a little more often on the forums.
4) Universal fit: Dam I hate that phrase. A guy I used to work with when I was an after school motorcycle shop tech used to say "Yeah, 'universal fit' means 'It fits nothing ' so now I have to make it fit". Many aftermarket parts are made to fit an entire range of makes and models, for stocking reasons. I always hate adding a cheezy rubber plug to an unused port on an aftermarket radiator tank, it's just another failure point for a leak down the road.
If it were me, I'd just replace the radiator with the cracked 'aged out' plastic tank with a good quality replacement, new Motorcraft thermostat and gasket, and move on.
1995 E350 7.3 Diesel, 4x4 high roof camper, UJOR 4" lift