Rabidhamster

your engine itself will have an effect on your exhaust tone/sound

the intake mani design of the mivec engine, and its cold tune will be more of an effect then the roving material in the muffler, however that material has an effect too.. packed muffs and strickly chambered muffs both show different tone characteristics as they warm up..

even my old carbed F100 with chambered mufflers sounds different after it's warm.

the new(er) efi multi cam setting and multi intake cars with packed mufflers will definately show a difference after they are warm.. just a nature of the beast.. your air path in and through your engine effect your sound though not as much as your exhuast...

in other words... it's not broken

evo_soul

if your exhaust is acting up and its a Magnaflow or any well known brand, you should take it to an Authorized dealer of any of those brand and let the shop guy see it. They will be able tell you up or down if something is wrong.

Its always best to ask someone who has expereience with the stuff as their daily bread and butter.

Sounds strange to me, tone may shift but if its getting louder over a long period of time i would check into it. I know there are 3 types of mufflers, restrictive is what you took off your car as stock, then there is asorbing and then there is reflective sound balancing / cancellation. some employ all three. iam not familure with Magnaflow lines so i could tell you.

But i would look into that bro, only cause if you notice something wrong this early in the game it may get worse later on