check your reliable source B.A.R ... there a bit off

Nascar didn't mandate mufflers, they simply put in a max DB level for Delaware and St. Eusatche, due to the fact that those tracks have house's in VERy close proximity.  St. Eustache has had the noise problem with every series that visits.
As far as the test day at Delaware goes, not every team was on mufflers, i actually think there wasn't a single team there using them.  I believe there were guys who stayed home from the test as they were afraid of the new Db rule.

You're right Schade. We tested up at St. Eustache last weekend. the 27 car without mufflers and the 7 car with mufflers. Alan's son was taking decibel readings, to see where the track stood as far as meeting required bylaw limitations.