I have a 90 civic si. i purchased a muffler for it and i will soon get some headers. i was just wondering if i should get a bigger mid pipe or just have headers, stock piping, muffler. do u think i should get a bigger pipe from the header to the muffler or just leave it stock between the header and muffler?

 

get bigger piping! 2 1/4

 

yea def bigger piping or u r defeating the purpose of the header and muffler. go 2.25 unless there is a turbo or supercharger in your future then go with 2.5

 

When I had a stock dx motor on my 88 hatch, one of the first upgrade that I did was replacing the exhaust. I bought a sport HKS exhaust through ebay for $300 and felt a big difference in power. Slightly quicker in accelaration and better top end.