Smaller overall diameter on rears would affect the stance.
Wider tread may??? catch the suspension (the 225s are pretty close anyway).
Lower profile would "harden" the ride.
All of which I'm sure you've considered. But would these "negatives" be all that noticeable in the "real world"?
But you would increase grip at the rear and lower it for flatter handling. Again how noticeable would that actually be?
Because you have the wheels and tyres available, trying it out would only have minimal cost and would be very easy to reverse if it proved troublesome. If it were me I'd give it a go. Unless someone has actually tried this out and knows of a good reason not to.