ok, i want to keep my n/a version n1 muffler. it's got a 2.25" inlet but i need to upgrade to 2.5" exhaust piping. is there any possible way, without restricting airflow, to mate the new 2.5" piping to the current 2.25" inlet? i was looking into the straight through design piping that goes directly underneath the gas tank with a small curve to the muffler.

here's a pic of what i am referring to with 2.25" piping(thanks to spoonfedhatch ):



the muffler shop says that since the muffler is stainless steel(and not aluminum), there's a chance that if they enlarge the opening, the canister can split in half. i would prefer the look of the angled n1 rather than say an es oval, but if i have to buy the oval, then i will.

any information and reasoned opinions are welcome. thanks.