From only hearing the CorkSport comparison video on YouTube, I think the Axleback system sounds better than the Catback system...but that's just my personal opinion. Go with what you think sounds best, but I personally don't think it's worth the money wasted going from this system you recently purchased to a different one that sounds similar.
I have a 2015 6 with the 6MT transmission. When I accelerate at a normal pace I frequently get hesitation/lagging in the low/mid RPMs. Before this car I had a 2015 with the automatic that I had bought new. Both had a similar issue. Has anyone else had this and found a solution?