Right, well in absence of any responses, I did what I should have done in the first place, which is stick my fingers in behind the wheels to feel how much room there is between the tires and springs
. Turns out I can barely get my index finger past the 2nd knuckle between the tire and plastic liner piece that sits between the tire and spring in the rear, so that tells me I *might* be able to get away with upsizing to 235/50 or 235/55 but a 245/50 would definitely be pushing it. Guess I'll just play it safe (and cheap) and stick with stock 225/55/17.