That's exactly right. It seems expensive upfront, but it's where you'll arrive after going through different frontpipes, midpipes, resonators etc. Only Borla's muffler is big enough to make a meaningful difference and they are the only ones who make something that big for that spot under the driveshaft.
I'm not sure how old your Perrin system is, but my Invidia Q300(itself touted as one of the quietest systems for our car) got louder after 2 years. I went through various Magnaflow resonators ( didn't last over 6 months ), Flowmaster Hushpower muffler (didn't quiet it down enough) and combination of the two. In the end only Borla made a significant difference, as it should since it's big enough to be a main muffler.
I only wish I'd bought Borla earlier before spending money on all the other stuff. Also you can get it for less than $900, I bought mine from FRSport.
