It gets louder because you are wearing out the fiberglass sound suppresent. So basically there is a point where you no longer have useful fiberglass in you muffler which pretty much means your muffler is useless and you are running off the cats suppressing any sound rather than the muffler. Hence why Glasspacks are so cheap. Also a muffler with a straight-through dessign infringes on your backpressure decreasing your torque.
If you want a solid muffler stick to chamber designs. ALWAYS remember, you get what you pay for.

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2003 Ford Ranger FX4 Level II
- JBA Cat-back exhaust
- K&N 57 Series Intake
- Poweraid Throttle Body Spacer