Croc

AEM CAV v2 is on it's way.

Next thing that looks like a good bang for the buck is to replace stock catalytic converter.

I want to be able to pass emissions tests - so i thought about Berk's free flow catalytic (didn't see other options for S).

it's pretty cheap and on paper supposed to provide ~80% of test pipe effect.

is this is a good adea?
what diameter should i go?
63 or 70?

currently i have stock header and exhaust - but in the future i would like to go for aftermarket ones. still don't know which ones exactly - but definitely something not very loud.

i think that most headers are 63 at output ...
most exhasuts at input are 70?

alSpeed2k

There's also Asura, it's more expensive than Berk, but it does have an additional bung that can be used for tuning.

dan_uk

has anyone dyno'd a hi-flo cat vs a testpipe?

Little_AP1_S2K

dan Uk i remember somewhere on a civic they tried both and it was like 186 whp with hiflow and 188 with a testpipe. None tuned.

Croc

so is 70mm is the one to go for?

alSpeed2k

What exhaust do you plan on getting and how soon?

Croc

not very soon.
probably something dual.
but mosr definitely a quiet one!!!

alSpeed2k

Exhausts also come in different diameters. That being said, if you are mostly stock right now I think it's best to go with a 63mm, the 70mm will be a bottle neck on your car.

By the way, for an '07, you should consider saving up for a flashpro.

Croc

bigger diameter can be a bottle neck?

chetly

Going from 60mm to 70mm back to 60mm is a bottleneck yes.