I say a little of both.
Neither Donna nor I were happy with the suddenly somewhat louder, uglier exhaust note, so I marinated on what to do for a couple of days. The shop had checked for leaks and there were none, so it was one (hopefully) of three things: muffler, catalytic converter or resonator. The easiest thing to check would be the muffler as it separate and held on by only two bolts and some rubber hangers. I sent an email to everyone in the MMC asking if anyone had a stock muffler for a 1999–2005 Miata laying around.
I got two replies. One person’s car was torn apart in the middle of a roll bar install and would gladly pull his to let me test with it. And Clunk, of the famed wrenching and auto advice duo Clunk and Thunk, had a used Borla muffler he would sell me for a mere $40 and even help me install it. The second sounded like a winner because if the muffler was in fact the issue and it sounded good, we were done. If the muffler fixed the noise and I didn’t like the exhaust note I could decline the sale and then pick up a used stock one somewhere or make the investment in a new Racing Beat.
At the last minute, Thunk volunteered a stock muffler, plus a whole mid-pipe (the piece with the cat & resonator) off a ’99 that he had inherited from a fellow racer. He said he’d give it the Clunk to bring over and if that was the way I went we could haggle over cost later.
I had doused the nuts holding the muffler to the mid-pipe flange with Liquid Wrench Friday night and then for good measure squirted some more on Saturday morning. I got the back of the car up on jack stands and with a bit of percussive persuasion I got the nuts off. About then Rudy arrived and brought out his foot and half long 1/2″ breaker bar and a can of silicone spray to get off those pesky rubber hangers. Ten minutes later we had mounted John’s stock muffler on the two exhaust side hangers and the flange. Started it up and revved the engine a few times. It sounded like, surprise, a stock muffler. This confirmed it must be something broken with the Racing Beat.
Because we missed the sportier sound of our previous Miata, one of the first modifications we did to the Emperor was adding the Racing Beat muffler. So knowing that both of us would be unsatisfied with the stock sound, I said to Rudy, “While we have it here, let’s go ahead and mount the Borla.” Even though they had recently been stretched and coated in silicone, those 2 rubber mounts were still a hassle to get lose. Got the Borla on there and revved it a few times — much more sports car-ish. I liked it, but I needed to get my co-driver to actually hear it too. We dropped the car off the jack stands and I collected Donna from the living room for a short test drive.
Overall it is a little louder than the Racing Beat at neighborhood throttle and when you stomp on the go pedal hard it is a little more than a little louder than the RB, but it is quieter and less ugly sounding than the Racing Beat had become. Donna pronounced that she could live with it. I paid Rudy for the muffler and both Donna and I are happier that we didn’t have to drop 10 times that cost on a new muffler.
Miata Top Transitions since 06/25/15: 165