So my stock catalyst was dying, and to replace it was going to be stupid expensive, so I went with a Megan (Blackhorse) header with a Magnaflow 50005 that welded in perfectly into the test pipe (2.25" it was a perfect fit). Got the header wrapped and all seemed to be fine...

...but the flange bolt holes did not line up well. 3 had to be adjusted, and the head converted to studs to prevent cross threading. Extra work but in the end it went in. Now, with the dump pipe activated, the exhaust is unholy levels of loud. Wow. With the dump closed it is much quieter, but still very "headery" if you know what I mean. The stock JCW exhaust seems to not cope well with the added flow or something, because it is now quite raspy. Not nice at all, and I may be changing it out for something with a much, much deeper tone. Invidia is my first choice I think.

Also there are still some vibrations I need to sort (probably heat shields against the o2 sensors or the tailpipes from what I can hear). But overall, I am very happy as it seems the midrange and high end has improved noticeably.

 

Converting to studs is actually a good thing, I personally think it should be done anytime you change manifolds/headers, the less you have to thread bolts into the head, the better.

The combination of CAT and Resonator controls the overall sound, so most High-Flow CAT's, will give you what you're describing with most any brand.

 

yeah the previous owner removed the resonator on the JCW exhaust. I guess I should put one back in? Any suggestions on a good one to give a deep tone that won't break the bank?

 

Sorry, I've kept my stock JCW all these years, I'm sure someone else will chime in.
But I would definitely do one, before swapping anything else out.

 

I was thinking of putting one of these in post-cat as it would fit with the JCW exhaust size and is fairly inexpensive. Magnaflow 10415. Thoughts?