Baz are you talking about the twin tip oval Varex where you lost the power or are you talking about the full 3" canon Varex?
When the 3" canon Varex is open its very close to a straight through 3" pipe right through the muffler. Its hard to imagine that would be a restriction over a generic muffler.
When the 3" canon Varex is open its very close to a straight through 3" pipe right through the muffler. Its hard to imagine that would be a restriction over a generic muffler.