Just installed FI HFC's and HR Y pipe
 

I was hoping this combo would've given me a little bit more sound. It sounds very nice, but not quite as loud as I expected. At least not from inside of the car. Just amplified the stock sound a bit. It's tough to tell, but I think I noticed a little more power in the butt dyno. Also, I hear a somewhat faint rattling type noise at higher rpm's. Is this rasp?

If I wanted get a little more aggressive with the exhaust note could I just swap out the muffler? What would you guys suggest? What else is there? Just a mid pipe and resonator right?

Test pipes/ART pipes will give you a louder note.

^Yes, ART pipes will give you louder note and increased performance, but just like other test pipes, you will experience gas odors if you have the windows down, especially after a pull.

OP, I am in the same situation as you. I just added the HR Y-Pipe, and really wanna add the ART pipes over Berk HFCs, but def. dont' want to compromise by having to deal with gas smell...
Let me know what you end up doing, it will help my final decision:biggthumpup:

you could cut out the OEM middy resonator and replace it with a bottle style resonator

Thanks for the replies guys. I'm not switching to test pipes now though so alternative solutions are welcome. In retrospect I may have went with resonated tp's but I'm sticking with the HFC's now that they are in.

Any insight on the faint rattling type sound I'm hearing?

I have read that sometimes the rattling can actually occur when the HFCs are improperly secured, and slightly hit metal parts while vibrating due to the air flow. Other than that, HFCs are not 100% rasp free.
Could be wrong, but that's my .02