ND Miata, RoadsterSport Race + 4-2-1 Headers?

[BenjaminB612]

I currently have an ND2 with the RoadsterSport Race Muffler, I see that the headers recommend going with a quieter muffler, but I am not concerned with noise as this is a track car and very rarely driven around town. Is there any other negatives other than the noise? A difference in power?

[Brian]

Love that Race muffler, but it was designed for SCCA CS use on otherwise stock exhaust system. When you pull the header and use highflow catless header the needs of your sound control change massively, and that Race muffler was not designed to handle it. Expect large amount of rasp and very big volume spike. At least here we have tracks with sound limits and open header and Race muffler will bust through the sound limits at tracks like Laguna Seca.