After long debate, I decided to pull the trigger on ERZ Performance high flow cats. While some of our site sponsors are offering great deals on Berk HFCs, none could match the price ERZ is charging for theirs. I placed the order last week, and 5 business days later the cats arrived at my door (Cali to Chicago). The following is a review of the cats and will be a work in progress as they are installed and tested.
On first look, the build quality is top notch. I've spoken with the guys at ERZ a number of times and they confirmed that the HFCs are full
polished 304 SS construction. Compare this to many CBE systems that mix 304 (better stainless) and 409 (so-so stainless) steels. The welds look great and they even packaged in some long, right-angle non-fouler bungs to further minimize the likelihood of CELs. We'll see how that goes with some driving time. For tuners, the cats come with wide-band bungs already included free-of-charge and are plugged with hex lugs for those who don't use them. ERZ uses 200 cell cores which I believe is par for the course with our HFC options.
1/16/10 UPDATE:
ERZ Cats installed this morning at Ultimate Z in Streamwood, IL. KT at Ultimate Z was excellent and had them in within an hour. No issues, no problems. I think he snapped two of the factory bolts but he said that has happened to most of the stock 370Z cats he's taken off. Then it was off for an afternoon driving around and testing them out.
On first start with a cold car, there was pronounced rasp and hiss. The exhaust note at idle is deeper. Revving revealed a noticeable off-throttle hiss as the revs drop and there was a good bit of rasp during the up-rev. I was a bit apprehensive with the results at first. About 10 minutes into my drive away from the shop, the cats started to settle in. Essentially, all the negative sound aspects became more subdued. Once the cats were at operating temperature, the rasp became quite minimal but slightly audible in the background exhaust note on WOT runs. The hiss also dampened and can be heard around the footwells on gradual off-throttle decelerations. While audible, I don't find it intrusive or a deal-breaker.
The overall sound has become deeper and richer than the Stillen CBE alone. It really gives the sense of a more 'open' exhaust note. Under WOT in the cabin, there's a nice full, deep sound that gets loud but never passes the too loud level. Even the loudest areas of acceleration (~4k RPM) never became painful. There is NO DRONE at all with this combination. That's to say, no panels rattle and your head never feels like it will explode. I didn't have a headache after having driven around all afternoon. With respect to rasp, it's very noticeable on cold start but settles down to a faint background rasp under WOT only once the exhaust heats up. While noticeable, I don't find it intrusive and it adds to the mechanical, racecar feel of the new sound.
A quick dB check in the car under WOT resulted in the Stillen CBE and stock cats at 78dB while the Stillen CBE and ERZ Cats were 88dB. An obvious jump, but not an ear shattering change.
I've now experienced first hand: 1) stock exhaust, 2) Berk HFCs with stock CBE (friend's car), 3) muffler delete with stock cats, 4) Stillen CBE with stock cats, and 4) Stillen CBE with ERZ HFCs. The stock exhaust was much too boring and prompted all the latter setups. The Berk cats with stock CBE livens the sound but adds more of the rasp/hiss without incorporating a lot of the deeper, more delightful elements. The muffler delete with stock cats is the 'wild man' option. It sounds ridiculous (in an awesome way), but is only for the already deaf or those who wish to be. The Stillen CBE with stock cats is smooth and rich with no rasp or drone. However, it just wasn't quite loud enough for me. The final combo of ERZ HFCs with the Stillen CBE increases the overall sound by a manageable level, deepens the tone, adds some 'wild man' flair, while introducing only a touch of the undersireable rasp (again, no drone). Overall, I'm happy with the combination and think this is where I'm going to stay. Time will tell with the old CEL light, but 50mi have been CEL free thus far.
In the end, I'd say everyone can safely add the ERZ cats to the options list and perhaps put them at the top given their incredible pricing. Really, who can pass on $369 shipped?
***Video Added, please forgive our commentary. We're children
. Unfortunately I was a bit limited with the videos given my winter tires. They kill takeoffs and we couldn't find a good area that was police and pedestrian free to really open her up.