i just got 4-1 headers for my gsr from a local shop, they told me the collector is 2.5",but when i got home i measured it and it was 2.0".
will there be a difference or should i go and exchange them for ones with 2.5" collector?

 

If they advertised it at 2.5" then ask for a header with a 2.5" collector. But what size is your cat?

 

i bought a 2.5" invidia test pipe

 

does anyone have a picture of a 2.5 collector measured?

 

the diameter of the pipe coming out at the end is the collector size right?