When you add a new exhaust have the small system taken out and put in a 2/1/4' all the way to your muffler then to a 2'' tail pipe will help big time on MPG and HP.
i'm gettin ready to upgrade my exhaust to 2 1/4 like you said, with a fairly quiet turbo muffler. would it hurt performance any if i just ran a 2 1/4 tail pipe too? or maybe dump it with a turndown in front of the rear axle? just to make it easier. its a stock 225 btw