Whats your reason behind wanting the sedan fenders? Wanting to run wider wheels? Want it just for the look? The rear fender has to be cut out and the sedan fender put in I know that much, which would require hours of body work.
12 WRX Sedan OBP - RA mudflaps and stock!
12 Impreza Sedan Premium ISM - old lady's ride
If he wanted to match the rear. But the front would be done in a weekend by the average guy.
It will look weird without the suspension or wheel spacers, which I wouldnt think arent very recommended. (spacers)