I originally put on the SuperTrapp to get rid of the embarassing stock muffler backfireing. But I got a wonderful surprise, I got a lot more power!
There was even more pull a lower speeds.
The SuperTrapp upgrade by itself made my pipe start to yellow.
The cure for this is to rejet the carb, so I did that. Then I polished my pipe with Blue Buster.
By the way, the SuperTrapp weighs 10 pounds less than the stock pipe.
Another thing that helps is the K&N air filter. This filter has a much better seal at the intake flange. It also increases the higher speed power when the engine demands a lot more air. I observed the same thing when I put the K&N in my Miata.