what in your opinion is the best cat-back system for the speed 6, hp gains sound.....
Yes the catback won't boost your hp performance much if at all. The restriction is in the upper half of the exhaust.
Youtube has a bunch of videos of almost any exhaust out there. Check em out back to back and pick the tone you like the best.
That's not quite true. Going from the stock, chambered muffler to a straight-through reduces a boatload of backpressure on the exhaust system. You should see higher-rpm performance gains from this. It may not be a big number, but you should see/feel that the engine is a little easier to string into the high-revs.
The muffler on the MS3 is not chambered. It is a straight through design. I don't know how the MS6 muffler may be designed. On MS3's we do not see power gains from changing the CBE until other mods get the power well north of 300 whp. The restriction is upstream -- the DP and the two low-flow cats before you get to the CBE. You are in the MS3 section. This might not be the best place to suggest to us what we might or might not know about our different exhaust system. lol.
However, since the OP also has an MS6, perhaps the better info might be available in the MS6 part of the forum?
and his point was your in the MS3 drivetrain section, not the ms6 exhaust section, hes giving insight of how the ms3 is designed because guess what, he has an MS3, and hes in the ms3 section
mods should just clean this up and move it, Please