I have a HKS Hi-Power, Mrev Plus and Z-Tube on my 2006 6MT. Will the crawford cats be a worthy addition? I am debating whther to add them since I hear it will make the car louder so I dont wnat to spend the $$ if its not going to make much of a difference

 

To be honest, I have the cats and almot an identical set up as your except for Nismo CAI and I can't really tell a difference, after getting MREV everything else is not as great. The car is a lil louder, but it is also depper in tone. I got a friend with just the HKS and mine sounds deeper.

 

I adde dthe cats to my G when it was stock. It made the exhaust note jsut a tad deeper. Only our fellow G drivers would be able to notice the difference. I have the Crawford plenum and cats, and the HKS. If you are goin, you can compare my exahust note to yours at the next All Florida G35 meet on March 4th.

 

bump......are the cats really worth the money for the gains???

 

This is the key question!

 

I got them put on at the same time as my fuji y-pipe and exhaust and I can def say that these 3 mods def made my car rev up faster and pull harder through the mid range. Now I can't really prove where most of my gains are coming from between those 3 parts but I am definatly happy with the sound and perfomance the combo gave me. I say they are worth it IMO.

 

I think they're worth it. Our stock cats are restrictive so their is a little power to be found there by switching them out to high flow cats or test pipes.

As for sound, changing out my cats didn't make my Borla exhaust sound louder only deeper.

 

I would go for it. So far I have only done the cats and header (plenum on the way!!!), and it made a noticable difference - sound and performance. Did I mention I would go for it?