Either High Flow Cats or Plenum Spacers.
i could buy either one for now. so Please need your advise
which one has more HP gain.
Thanks

 

Both would add the same amount of hp around 10whp. The HFC's will cost more but will make your car much louder and would be harder to install. I say go for a MD spacer.

 

you could do what i did....grab some OEM cats, a drill, and drill out the secondaries to get some HFCs

 

Save your OEM cats and buy some Helix test pipes...

 

I did have Test pipe on mine before. the sound and the gain was AMAZING.. however with the top down, Exhaust fume was too much to handle.
when rolling it would come stright in and you could see the exhaust partical inside my car, would get on my cloth.. made it smell like exhaust all day long..
it was horrible..
but i did feel an incredible gain from it.. thats why i am asking
HF cats or spacers.?? hmmmmmm which should i do first

 

just to add.. i have Nismo Exhaust, Engine torque damper, Intake so far.

and if one or the other please post why. thank you in advance

 

go with the 5/16 spacer and UR Crank pulley! By the way, what kind of test pipes did have on ur car??

 

Megan Res. Test pipe

 

oic..i jus hope my APS test pipes doesnt give off that much of fume and rasp.

 

Plenum spacer hands down.

 

ok, quick question.. w/ the spacer, do you have to remove your strut bar for good?(cause of the clearance)

 

not with the 5/16"

 

hmm seems like Spacer it is~ thanks guy!!!!
but Why not the HFC??? any reason why?

 

HFC are good, but when you are comparing the two, the Spacer will make more power

 

haha that was fast reply~ Thanks rickdogg
I am going to Andy on monday to pick these baby up~ you wouldnt happen to have some used ones laying around no??
thought i ask

 

That is what you do when you are sick as a dog (no pun intended) and can't go out and get worse I don't know if you are referring to the HFC's or the Spacer, but I don't have either in used condition

 

damn you sick man? hope you feel better~
and i was referring to the Spacer. i guess i am going to see Andy since he has it in stock
Thanks Rick

 

so with the 5/16 spacer the oem strut brace can stay? what other sizes do they make? what is the difference in whp between the sizes?

 

We installed a 5/16 spacer on my buddy's Z friday. Strut bar stays, it has spacers too. Ive got an 03' base with short shifter and injen SES and he has test pipes and injen CAI. We race all the time and the car that gets the jump wins. But after we took of his 1st gen. Ingen CAI and replaced it with the JWT pop charger and added the spacer, well... Lets just say we wont race again till my pop charger comes in monday(thanks fiddyBoy). Spacer is a no brainer.