When I ordered my DA50 (and yes I have had it for about 2 weeks), Dave @ DA said that with the BCM, you would loose a few hundred rpm. But he said if you cut about 1/4 of an inch off the exhaust stacks you would gain that rpm back, and as davham put it, makes it sound more "manley". I still have yet to receive my muffler. I guess BCM was/is having a problem supplying the demand....