Theres 2 Mazdaspeed exhaust systems, one part # being GRMS-8M-K06 (Mazdaspeed USA Dual Muffler Sport Exhaust) and the other being QSEA-40-10 (Mazdaspeed USA Cat-Back Sport Exhaust) . These were mentioned in a thread a while back, but I was wondering what is the difference between the two? Is one more quiet than the other? Do they both put out the same increase in power, and if so, how much? I googled the part # and it lead me to Andysautosport.com to where I found a difference in price.

 

Exhausts wont net you very much hp, so don't buy one based on that. Just buy what sounds good to you.

If I had to guess the difference I would say one has dual mufflers and other does not?

 

The dual muffler is louder and sounds better. Go with that one.

 

Agreed. I have it, it sounds awesome.

Both are pictured here: http://www.mazdamotorsports.com/pdfs/msacc.pdf

 

You might as well just go with the racing beat rev8 exhaust. It's comparable to the Mazdaspeed dual canister.
IE: Zero freeway drone, no ricey/tingy sound, deep bass, perfect fit, no weld issues, amazing sound at WOT.

 

^+1. Exactly what I was looking for. Thank you. I can't really get the Rev8 exhaust, my car is still under warranty so I need something compatible that won't void it.

 

It will not void your warranty unless they can prove It actually did damage to the car

 

RB's catback is heavier than the stock one though while the mazdaspeed one is a bit lighter.

 

The RB system is also backed by proven dyno results, where the MS isn't

 

You will see the same gains with almost any catback so that's a moot point.

 

Louder as in wake the entire neighborhood whenever you touch the gas pedal louder?

 

No.

Here is mine with a pretty crappy mic.

http://www.youtube.com/watch?v=k9fPHpKWns8

Stock CAT.

 

Very nice!

Is it reasonably quiet when just commuting along at low revs? Point being... if I was to take people out to dinner in the backseat, would they be painfully aware that there's a "sport exhaust" installed even while driving along casually? Or does it tend to only sound "aggressive" when getting on the gas?

 

Will the GRMS-8M-K06 Sport Exhaust fit a 2009 RX8?

 

It's looking like GRMS-8M-K06 is not compatible with 2009 models because of the positioning of the outlet tips.