I recently needed a new muffler on my '90 Legacy wagon, and took the car to a Meineke dealer to get a replacement. After I getting the car back, I noticed that the new muffler had only a single pipe exiting from it, while the original Legacy muffler (and all subsequent replacements) was dual tipped.
The Meineke guy apologized, said that he hadn't realized the original was dual tipped (the back of my muffler was badly rusted out), claimed that single or dual tip should make no practical difference, but offered to install a dual tip muffler at no charge if I wanted him to. The only problem was that it was the end of the day, the shop was closing, and I would have to bring the car back at some other time to have the work done.
Here's my question: should it make any practical difference whether the muffler is single or dual tipped? I'd prefer not to waste half a day getting the muffler replaced if there's no practical reason to do so. On the other hand, it makes sense to me that a dual tip muffler might offer less back-resistance than a single-tip, and thereby effect the car's performance. And it may be my imagination, but the car does seem a bit more sluggish and a bit more prone to a slight back-firing on deacceleration.
Any advice would be greatly appreciated!
Zack '90 Legacy wagon auto 155,000 miles