Mufflers and gears

Is that a 4 cylinder T5? If you're not concerned with performance, then go back to a stock 3.08 or 2.73 rear end, that'll keep you in one gear longer and you'll be at much lower RPMs on the highway. If you ask what the best gear for street is, most people are going to tell you 3.73, and i don't think dropping down to 3.55 is that big of a deal, so you won't get what you're looking for.

For a DD street car, I always recommend 3.55's. For mufflers, 3 chamber flos are nice, or my personal fav, the Hooker aero chamber.

As far as the QUIETEST muffler, you can't get much quieter than Dynomax Super Turbos. I ditched mine because, even though I was wanting something quieter than the MAC's that were on there, it sounded worse than stock - even at WOT, they were pretty blah. The Pypes Violators I have on there now are no louder than the Super Turbos at idle or regular driving (actually a tad quieter inside), but they roar plenty when you romp on it - nice raspy tone like a chambered muff above 3k RPM, but they're a straight-through design.

As far as gears, it depends what you're running for a transmission; if you've got a 4-banger T-5, first gear is gonna be so short and semi-useless that it won't matter what you put in the back. I'm running 4.10's behind a regular V8 T-5 and first is a little brief, but not so much that it's useless for regular driving. Sure, you could downgrade to something as low as stock 3.08's, but the only thing you'll thank yourself for in doing so is maybe picking up a bit of gas mileage - I do NOT miss the 3.08's I had in my previous notch. Being able to step on it in 5th on the highway to pass/merge is nicer than having to jam it down into 4th or 3rd just to get some oomph out of it.