There is no way a 1/4" is going to make a difference as that pipe sits inside the muffler.

Once you put the clamp in place and tighten the clamp, its not going to move, thus the reason for my comment earlier.

Now if you had say a couple of inches, then you need an extension.

I removed the first muffler from my set up and I needed a 20" pipe that I had made to make up the difference from the end of the cat pipe to the exhaust pipe.

A 1/4" is nothing in the whole length of that setup. Things can me moved to make up that difference.

Matt