We had the discussion about the possibilities of bad results when
mixing different exhaust components. From collective experience I think
we can agree that the section 3 doesn't really add or subtract significant
power. The scoops/bmc/cf filter combo definitely adds power. From the dyno numbers it looks like your car is down a significant amount compared
to other cars.
Unfortunately it seems like the only way to really know is to swap the
x-pipe back to the stock resonator-xpipe. Either that or a thorough check
to ensure you have no leaks or other problems...or maybe even a
second "opinion" on a different dyno? The last being the easiest thing
to do...the others being a pain in the @ss.
I'd love to see and hear what the Dinan midsection sounds like with the
Dinan section 3. I would go this combo but it's not available for the M6
and I'm a little disappointed with the pricing. Offered without high-flow
cats the price point feels about 1k too high. But I suppose you have to
pay to play.