Rich,
The only difference between teh Denso plugs and the BR’s is that the Denso’s draw half the amperage from your battery which in theory should keep your battery from dying on the track during a race and causing a fouled plug. In my experience the Denso’s were more fickle than the BR’s and would foul easier…so bottom line is don’t waste your money on a Denso and replace your plugs every race.