Depends on the tips. For the most part, I'd say no. The '65/'66 GT tips with louvers, though, definately change the sound. When I had them on my last '66 coupe, it sounded much quieter with the tips on, and kinda baffled from the louvers.
If you always do what you've always done,
You'll always get what you've always got
Tips can make a small change in sound. Those 3 1/2" tips tend to make it louder and lower the pitch slightly. Length also plays a part in pitch drop on large dia. tips. Stay away from those "coffee can" resinator tips. They do change the sound, but to an obnoxoius loud. They do nothing to improve tone quality.
You can never have too much power, just not enough traction.