I too was in the same predicament as @
Armin93 a while back with the UEL header & Perrin CB, best solution was the stock CB. Still I wanted a little more noise but less than before so I managed to find an STI AB which opened up the noise hwy again but not as loud as Perrin. I had an additional resonator in the midpipe added which helped a little by taking some of the bark away and I guess it become livable to me as a DD although it's not one atm. What I'm trying to say is there's very little room under our cars for big midpipes & the best way to shut her up is probably the rear mufler as the stocky does it really well.
Another thing to note is you need to give exhausts a few thousand kms to carbon up & re-evaluate noise levels then.