Well, I didn't know what a C4 was so when I searched it sounds pretty good for a 4cyl. Low hp but pretty awesome torque. If you weren't going to tow I'd say go for it. Mountain passes and a heavy rig? How many times will it do that before problems come. Depends also on how you would maintain it too.
It is a bit under-powered for what you may have in mind in my thinking.
Keep looking unless you drive it and fall in love with it.
I appreciate everyone's input. I pressed the guy a little more about the engine and it turns out it's a C7 with 250 horsepower. That C4 certainly didn't make sense since my minivan has twice the horsepower it has. He didn't really know what he was talking about.