I have an AP2 with SKUNK2 exhaust and FIPK intake, my 60mm resonated test pipe is over and i whant to know what is the best for me between buy another 60mm resonated test pipe, a 70mm test pipe or reinstall my stock cat since i will stay N/A?

 

You're going to want a 70mm test pipe to match up with the diameter of the exhaust unless you're worried about emissions. From everything I've read, the stock cat increases in-car drone, I have the skunk2 with 70mm TP and it still drones alot with the top up between 3k-4k RPM so I couldn't imagine having the stock cat on. With that said, I highly recommend the berk 70mm tp with CEL fix, I've had it installed for 5k miles including a trip to the dragon and I've never thrown a CEL in my MY04.

 

It's going to be loud as mofo!!

 

with stock ecu and header, will i see benefit with test pipe or if not, i will re-install my stock cat

 

Not enough to notice. But it will drone like a mofo!! With a stock cat. Get a test pipe and the drone Won't be as bad.

 

^+1

 

Let me be clear about "lessing drone"
I had the Skunk2 exhaust and let me stress... its a VERY loud exhaust.
I ran with 3 different cat setups and i will make notes of each.

Stock header & cat:
-Interior vibrated worse than with my innovative mounts
-It would make your brain hurt if you had to drive with the top up
-Scared the piss out of several drivers when i passed them on the interstate
-Got pulled twice on campus for setting off car alarms in my parking garage
-Droned so loud i couldn't hear anything in my car, people talking, radio, etc.
-I bought ear plugs while i waited for a better setup.

Berk Header, Berk HFC:
-Interior didn't vibrate once car was warmed up
-Deeper rumble and sounded better, but drone
-Drone toned down a bit, but still f*cking loud as balls when cruising interstate (did i mention drone?)
-Still couldn't make a long drive without ear plugs, still drone!
-Got pulled (again), let me stress i was just rollin about 3k rpms going up the garage ramps. Thats all it took to set alarms off.

Berk Header, Invidia Test Pipe:
-No more vibration to speak of, even when cold
-Had a "wet" sound to it at certain rpms
-a little (very) raspy at vtec
-Could talk (loudly), but it was pushing it, still no radio
-Overall, it made a much raspier "ricey" sound than in its normal form.
-Highway was bearable but not pleasant

Basically, there was no living with this exhaust comfortably so i sold it for a HKS 75mm single, which is still loud but not nearly as bad.

Meant to add, it actually melted all the baffles out. I have a video somewhere of me shifting 9k thru 5th and it was just shooting pieces of the baffling out (looked like hundreds of sparks on each shift and then decel) lasted maybe 6,000 miles total? Cheap pos imo.

 

Had skunk2 with 60mm berk test pipe. Super loud resulting headaches With the description close to what Importedpower said with berk header+test pipe.

I tried silencers for it, helped a little but not much.

So sold it and no regrets. Now with J's header, 70mm pipe and T1R 70 Dual and couldn't be happier.

Based on my experience, you will not make it less droning or less loud significantly.
With cat on, it may be less loud, but drone will be very bad. If I were you I'd sell it and get some quality and sound proven piece.

 

General concensus said to have the same test pipe diameter than the exhaust said but stock header is 60mm, skunk2 is 70mm pipe that reduce to 60mm (skunk2 sold it as a 60mm exhaust), my question is what's best size for the test pipe? I have a great result with the 60mm resonated vs stock cat and its very cheap priced, 70mm is 3 x the price, its worth the price or best to stick with the 60mm (N/A and only K&N FIPK)!

 

Skunk2 exhaust is 70mm I believe. As everyone else said buy a 70mm test pipe to match up to it.