X-Tech,
Concrete-filled.
or Lead-filled.
Maybe the exhaust system should have been allowed to be placed in the trunk.
Some of those 'special' mufflers required two-people to lift it in the trunk.
Of course, no one said there were legal 'silencers'.
See, thats why they should have allowed 9.25" slicks for the top stock classes (9.99 and under).
8" wide inch for middle stock, and 7" wide for junior classes.
More Traction,,,Please