i have 27 inch chrome-3 1/2 inch tips.
Can tell ya this-It definitely alters the exhaust note, more big blockish resonating, sounding and makes it a bit louder as well. if loudness is not what you want, go with the 2 1/2 mac tails.
I have learned the only way to make the entire length of the pipe the almost the same is to sand (320 wet sand) down the pipe before it meets the chrome tip, and then brillow it up and then polish it. but everytime you wash the car, you must brillo it, because it will eventually turn colors and will not match. this is how-I got my 27 inch chrome tips to blend intot he regular pipe and look as one.
Lata Ant