The car will behave worse with 275's up front on the street. If you are on a road course, or auto x, then I would go with them. I ran them on 2 SN95 GTs for a lot of miles, and hated them. Each time, I quickly switched back to a 255 up front. More weight, more resistance with the weight, etc. They do look good though. Some people like them, but I am very keen on how the car responds with different wheels/tires, and I just don't like the weight up front.
With the 275 up front, your car will track more. It will pull harder to each uneven surface in the road, or pothole. I never liked it in a mustang. I still run a 265 in the front, even with 775hp in my car now. I won't go bigger in the front unless I get in to road racing. I would like to go to a 255 on the street in the future.