Jcosta Im actually I'm thinking of switching to ARK test pipe. How was the sound and acceleration?

Zoren did the CEL light ever pop up with your ARK HFCs? Im leaning toward them at this moment.

^ yes it did ... But that is expected as you open up your exhaust.
Been driving with it for years never had any issue. Car still runs great!
You need to have a tune if you want to get rid of it. Plus you get the best performance out of your mods with a tune.

yeahh I know about it the tune. Was just wondering about the CEL light. I had a G37 before the Z and I went through exactly the same thing. HFCs hiss, CEL light.
Although I did manage to get rid of the CEL after some time with the angled fouler. I tried everything else with steel wool and short foulers, nothing was permanent but the angled one really got rid of the CEL once and for all. So I guess i might do the same with the Z.

I had the test pipes first with the stock Nismo exhaust and then I purchased the Invidia cat back. You don't really hear too much of a difference with the stock exhaust. Test pipes and tune made quite a difference in acceleration and responsiveness, but the Invidia cat back really woke the car up in the low to mid range area as well as significantly improving the quality and volume of the sound.

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