cars

So I bought a car from a relative because I could afford that, they bought a fancy boutique version of this car (Chevy Cruze) that has, by default, 18 inch rims. I live in a shitty midwestern USian city and of course this thing can't handle potholes and the tires leak if you look at them funny. I've been limping along as long as I can but a pothole destroyed another one and replacing these stupid 18 inch tires is expensive. I've had to replace them twice in the last year, it's absurd, and they're of course way more expensive than a normal person tire.

So I'm looking at replacing the entire wheel set so that I can get a 17 or 16 inch wheel with more reasonable and cheaper tires. Is there any reason to be afraid of a certain size or wary of downsizing at all? I go on some site like Tirerack and it looks like I can get a set for a few hundred. My mechanic said this isn't a problem, that the chassis is identical to the less boutique options, but I'm not a car person so I would love a second opinion on this before I spend a bunch of money again. Things to look out for, free wheels (lol), any helpful advice is appreciated.