I spent an insane amount of time digging through old threads while choosing these parts. I was always most interested in opinions posted by people who had first hand knowledge about the product they were discussing. So here are some of the concerns I had, and how well these mods lived up to my expectations. Since I had the MS exhaust installed a week before the Supercat, I'll give my opinion of the exhaust by itself, then the combo.

MS Dual Muffler Exhaust
I purchased the exhaust from Med Center Mazda in Birmingham. Complete side bar-I have used Med Center several times now. I had an AT 8 (which I have now traded for a MT) that was the bane of existence for a few months. Lots of issues. Thankfully Med Center is only 10 minutes from my apartment. If you live anywhere near Birmingham I absolutely recommend these guys. Especially if you need warranty work and you have to go to a Mazda service center anyway. I called on a Monday and told them to schedule it so I could drop it off and pick it up the same day. Took it in that Thursday at 8. They called to let me know it was ready just after 3 that afternoon.

Worth it?
As anyone that has done their homework should know, no performance difference. But it sounded GREAT. Not ricey at all, and the larger tailpipes look awesome. With normal driving and acceleration I only heard it when I wanted to with the stereo at 10. It did get a little louder after a couple of days, but same effect as before with the stereo at 12. I paid right at $850 with the install. Could be cheaper, but not rediculous and you keep your warranty. This is definately only a "feel good" mod, but it a "feel really good" mod IMO. There are louder exhausts out there (Borla). But if you're looking to improve the sound of your 8, but don't want to yell "Hey, look at me!" every time you step on the gas, I think you will be very happy with the MS exhaust.

RP Supercat (+MS exhaust)
I had a really hard time with this one. The Supercat is the clear crowd favorite, but I was concerned about my car being too loud. The Supercat is always described as "loud". Expecially when it's paired with an exhaust. So I was leaning towards the SR Motorsports HF cat+resonator. I just couldn't shake 2 things. Reviews and opinions were mixed at best. Not to mention...quality aside...these guys are SERIOUSLY overpriced. Really, $450 for the cat and another $80 for the resonator. I haven't even gotten to the mounting kit OR S&H yet! I decided to call RP and ask if there was any way to put a resonator on the Supercat. Best thing I could have done. Anyone whose curious about the redesigned Supercat...READ

RP rep: "Due to the high exhaust temperatures created by the RENESIS engine, our original Supercat was made entirely of metal, including the filters. It was the best way to ensure the converter didn't fail over time. But we have developed a new ceramic material that tested beyond the maximum temperatures created by this engine. Our new Supercat uses ceramic filters. Which are smaller, lighter, and greatly reduce the noise."

I pulled out my credit card and ordered the part before I got off the phone (Remember how much the SR cat is? $450-just the cat. No tax, S&H, nothing else):
Supercat, mounting kit, tax, and S&H = $445

SR MOTORSPORTS CAN KISS MY THRIFTY ***!!! I've had it on for 3 days. Install was kind of a pain. The front bolts were rusted pretty solid and I had to use an impact wrench on the rear ones. Plus you need like 4 different sizes of sockets. But the actual work is about as straight forward as you're ever gonna find.

Worth it? HELL YEAH! It does add some descent volume, and the exhaust note is a little higher. But I haven't noticed any change in the exhaust odor, and I can still drown it out with the stereo at 15 or 16 (unless I'm really getting on the gas). But even if any of that weren't true...there is a very noticable performance difference. The car accelerates faster and pulls a little harder starting pretty low in the mid-range. I don't know if the difference would be as drastic for everyone, but I had a nice jump in top speed in a single gear too. Ex: Before, 3rd gear redlined -9k rpm- at about 93mph. An hour after I finished installing the cat I was running 114mph at 8k rpm. Unfortuneatly I was heading towards some well known speed traps so I had to back off. I would definately say I got what I wanted out of my $400.

Bonus: MPG
After I was done playing, I went back to normal driving habits. My last tank got about 3 MPG more than usual. I hope it gets even better after I get the CAI installed.

 

Cool write up. Thanks for the info.

One thing though... This comment:
Might have a few people wondering "WTF?" Since it's the gearing that would determine speed @ RPM not engine performance. I'm guessing that maybe you were in 4th for 114@ 8grand...?

 

Nice write-up. That's the same set up I was using until I put my stock cat back on. It was noisy, but not too loud.

 

Thank you for posting this! I have the MS Dual exhaust as well, and have been thinking about getting a high flow cat to help with performance, but I don't want it a lot louder.

Do you notice a louder droning on the highway? I don't mind a bit more around town noise or louder at high rpms (in fact it might be fun), but I don't want to listen to a loud drone for an hour or two. I realize mine won't have the exact same sound since it is a 4-port motor, but it should be similar.

Was the resonator still an option on this cat if you decided you wanted it? I'm thinking I'll try it without a resonator and then get one later if i need it, assuming that is possible.

If the mpg gain continues to hold, that would be a nice bonus as well.
Thanks again!

 

I'm sure you're right. I'm probably just remembering things a little wrong. I was pretty excited. It seemed a little weird anyway. Now I know why.

 

It is a bit louder, but mostly just when you are building speed or on a steep incline. Bump the stereo up a notch and set the cruise. I doubt you'll even notice most of the time.

...and yes, it is fun. I don't think I even turned my radio on the entire next day.

 

just wondering... is the ms exhaust a LOT louder or barely louder? i want an exhaust thats about as loud as the stock one.

 

Greddy SP2! It's so quiet!

 

It really depends on how you're driving it. If you're heavy on the gas (like I usually am) you'll notice a pretty big difference. But when I was in traffic and accelerating fast wasn't really an option, there was almost no difference. Especially if the windows were up. That isn't true with the Supercat though. But like I said in my original post...with just the MS exhaust, the radio tends to drown it out. With the windows up and the readio at 14 or better, you won't even think about it.

 

the sp2 isnt that quiet. not compared to stock.