1. Does anyone know the size of the stock ITR resonator? How does this resonator compare to an aftermarket piece?
2. I currently have a 5zigen Fireball Exhaust. But, now that everyone and there mother has one, I wanted to change mufflers. The piping on the 5zigen is 60mm, but most aftermarket mufflers like Maganflow and ES only come in 2.25" or 2.5". Would it be better to go to the smaller 2.25" and create a small restriction or would it be best to go to the 2.5" and lose velocity?

Here are my mods: b16a (99 Civic SI), CTR CAMS, ITR Valvetrain, 11:1 Compression, ITR Intake Manifold, Spoon TB, Comptech Icebox, JDM 4-1 Header, 5 Zigen Fireball exhaust.
I dynoed 167 whp. I already have the ITR resonator attached to my 5zigen piping, because the original resonator cracked after only a few months. I don't plan on doing too much more in terms of modifications.

I guess here are the options in order of least expensive to most expensive:

1. 2.5" Carsound Cat--->60mm 5Zigen Piping/ITR resonator---->2.25" Magnaflow/ES

2. 2.5" Carsound Cat--->60mm 5Zigne Piping/ITR resonator--->2.5" Magnaflow/ES

3. 2.5" Carsound Cat--->2.5" Magnaflow Resonator--->60mm 5Zigne Axleback Piping--->2.25" Mangaflow/ES or 2.5" Magnaflow/ES

4. Brand new 2.5 inch system all the way back


Sorry for the long post everyone. What do you all think. I don't really want to spend all the money on the 2.5 inch system. One because I think it may be too big, and two because it is more expensive. But if the other systems will be also be creating flow restrictions and decreasing horsepower than I guess I have no other option then the new 2.5" system.


Thanks again,

Cruzer

 

I would probably go with #4. Look at the Skunk2/RSR Invidia catback. It's 60mm piping and very well made. It's also an N1 style exhaust. I don't see many around here, and quality and gains are nice..
Very nice mild setup Cruzersi00

 

Well option 4 is actually bigger than 60 mm. 60mm is equivalent to ~2.38". I have a feeling 2.5 may be too big.

Cruzer