I've been doing a lot of tinkering and wasting money on my exhaust system over the past several months and I thought I'd share my experience.
After adding a JB4 and intake I wanted more and decided I'd start working on the exhaust as the target mod.
1) Removed resonator for $70 at local muffler shop
HUGE mistake IMO, I highly discourage anyone doing this. I hated the sound in drive thrus and driving through my company parking garage each day and how the drone noise in the cabin increased significantly and at very specific RPM's - 2.5K and 3.1K.
2) Added Neuspeed downpipe + cat-back
A local shop doing the install too easily persuaded me into buying a Neuspeed downpipe rather than the brand I had selected. Since the loss of the resonator was still bothering me I also saw Neuspeed had a cat-back exhaust with a resonator and marketing claims on their website as "carefully designed to have minimal drone inside the cabin" .. perfect I thought - order away $$$...
On my way home after the install I was only thinking of how embarrassing this was going to be with work colleagues in the car on lunch hour, and was also worried my neighbors were going to come over to my house bitching. The drone I had at 2.5K and 3.1K w/o the factory resonator was now extremely annoying inside the cabin and that RPM range was unavoidable. I took it on a highway trip for 2 hours and actually developed a headache and couldn't find a way to enjoy the sound system any longer.
3) Add another resonator to kill this drone?
I liked the looks of the neuspeed system and with all the $$ I spent I was trying to keep it so I did some research on drone removal and found a Vibrant 3" Ultra Quiet resonator #1142 that looked good and had really great reviews. Order away $$$ ... took it into a muffler shop and had them weld it into place. No such luck, more wasteful dollars down the drain.
4) Can i insulate that drone away?
Using my stereo upgrade experiences I decided to buy a XXXL roll of Focal B.A.M. and insulated my hatchback door, hatch floor area, and all four doors to better insulate the car. Nope!
5) This thing has to come off !
I took it back to the shop that talked me into the Neuspeed. We decided to put the stock exhaust back on and Neuspeed was nice enough to provide a midpipe to work with the stock system.
MUCH better I thought after a few days of driving, however, that damn cheap sounding drone at 2.5k-3k RPM was still there, just not anything as loud as with the Neuspeed cat-back.
6) Where is that stock resonator?
I grabbed the stock resonator out of storage the next Saturday I had free and off to the muffler shop I went. After another $80 to put the stock resonator back on I was blasting down the road thinking YES! I had a little downpipe attitude in the exhaust system noise but the drone noise in my cabin was complete GONE.
I've also been fighting with downpipe rattles since day 1 of putting the Neuspeed system on. I've bent the heat shields as much as I can out of the way around the firewall and the ones separating drive shafts and exhaust pipes but I still have a rattle when letting out the clutch from a stop or going downhill slowly in 2nd gear. Going to try an engine mount insert to limit the engine movement.
Lessons learned
A) never underestimate the R&D that the factory engineers have put into the exhaust system created for a car ... and if you remove components make sure you save them in case you want to put them back on
B) never believe the marketing hype on a performance parts website, you will have no recourse from their lies
C) don't let a shop that has a favorable relationship with a parts supplier/distributor persuade you away from a brand you have researched as providing good results from other forum members
