i am puting a si in my 89 hf and plan on getting a cat back or more likely a custom exhaust made...there is no catalytic converter on the car now. is there a need to put one on? i dont want my car extremely loud but does the cat. conv. even deaden the noise on it? if i get one it will be a high flow...what should i do??

 

the convertor adds some backpressure and helps with sound. it also helps the air we all breath be cleaner