Raptor muffler $21.95

So I've been driving my car around for a while with headers, and ORY with no muffler. I recently drove it home (4 hours) to my parents house. I decided it was time to grow up and the car was too obnoxious. Being that money is tight right now I wanted something really cheap. So I bought a "Raptor" muffler from O'Reilly and welded it on. It only has a single outlet which sucks... The construction seems to be really good, the sheet metal seem to be really thick. The sound is not bad either. My question is... what is the major down side to going with a cheap muffler such as this? I' not all that concerned about sound, just flow. I known it probably doesnt' flow as well as a flowmaster or dynamax but surely it's better that stock right?

A 22 dollar muffler with a single outlet I'm sure is not flowing as well as a bigger name muffler or full catback for that matter.

I was running open exhaust for a while but stuck this muffler back on to pass inspection.. I still have the same question..