Just put the stock one back in lol. Then buy a test pipe. If you sold it to you for $80 it mostly is a crap header.

 

How would an $80 header be an improvement over the little gem that's on the car already?

Take it off, destroy it and then sell your car

 

Most of the headers available aren't any better than stock, and the ones that are better would not be sold for $80. The stock header is very good, so just throw the one you got in the trash. As for the test pipe, it needs to match the size of your exhaust. If you plan to keep the stock exhaust, then get a 60mm test pipe. If you plan to get a 63.5mm exhaust, then get a 63.5mm test pipe.

 

^^What everyone else has said. Match the test pipe size to the size of the exhaust you have or are putting on the car.

 

So you guys reckon I'll gain a little bit just be using the stock header and exhaust with a 60mm test pipe? Any tuning required? TIA!

 

This thread will be helpfull about the test pipe.
https://www.s2ki.com/forums/index.php?showtopic=842575

 

i read the thread i learned alot....but now i have a question stock headers and stock exhaust w.70mm test pipe ??? how would that run ?

 

If you're asking that question, then you probably didn't do a good job reading it.

BTW, the S2000 only has 1 header.

 

from what i gathered, it would be best to run a 60 mm test pipe since youre on stock internals with everything else.

 

The best and easiest way to determine what size test pipe that would be best for you is to ask yourself this question..What size is your exhaust system? Well the OEM exhaust is a 60mm..there is your answer. Putting a 70mm test pipe on a 60mm exhaust isn't going to make anything better, it is best to have your entire exhaust 1 size so if flows smoothly and doesnt have any reductions.