The stock tC is fairly quiet, and I like that. What are the best engine performance mods that don't have the hissing, raspy sound? Does more power really mean more noise? If so, preferably deep, low, and quiet.

 

You could get some pullys, they won't alter the sound at all and from what I've read, they really help with throttle response.

 

^That is true. NST pulleys are a good way to add power and not increase noise pollution. You could also add better tires, suspension modifications, and weight reduction to make your car faster while keeping it quiet.

 

supercharger?

 

Pulley for sure... (and mine's for sale, actually.)

I loved what I had, injen intake / cc spipe / precisionmuffler exhaust. It was marginally louder than stock but definitely faster.

Tires make the biggest difference for overall performance. Suspension work will drastically increase your handling, more so than power mods will increase your acceleration.

Weight reduction is also great, but on the tC, you're asking for a lot of road noise. The stuff in the interior is basically your only sound reduction. You can strip it down to the bare sheetmetal in a matter of a few minutes with a socket set.

 

Gotta go with the Precisionmuffler.com axle back for a great sound and easy installation. :D
We have a special going on right now as well.

https://www.scionlife.com/forums/viewtopic.php?t=146854

 

K&N air filter, then a pipe running down to the front bumper. cheap, effective, CARB LEGAL, barely any noise diffrence, better gas mileage.

 

Is the Injen CAI all that much louder in otherwise stock form? I heard the TRD supercharger adds a slight whine noise but is still pretty quiet. That's the kind of upgrade I'm all about. Is there anything cheaper though? I really don't care for the hissing fart box noise that flattens the ears of nearby dogs

 

Intakes are louder, yes.