I tend to agree with "ds". When GM commissioned the 215/65x15 tire back in the 80's, it was designed to replace the 205/70 14 with a similar diameter, but wider 15" combo. A little research time on the tire mfr's websites would be time well spent. Speaking as a retired autocrosser and circle track racer, I personally would never mount up a tire on one of my cars that had less load capacity than the OEM size. Years ago, before low profile tires were plentiful, the lowrider dudes would stretch out 5.60-15 VW Beetle tires on 7 or 8 inch wheels for their Impalas or other two ton cars because it looked cool. Maybe that's why "low and slow" was the style, since taking a fast corner on a tire designed for half the weight load was near suicidal. Sure, that's an extreme, but I hope I made my point. Remember, the highest load in cornering is on the outside front wheel, so it's definitely not the place to compromise performance for looks. As I said, do a little research, and you're sure to find a tire combination that both looks good and outperforms OEM. You might consider going with a 235/60-14 with your 255/60 -15 rears. You'll still have rake and the "big and littles" look, but enough front tire to out-perform the stock setup in a corner.
Sorry for being long-winded; This week's sermon is now ended.
Bill