Basiclly it allows the gases to pass through the exhaust easier 😃 ,
200cpi =200per inch,100cpi= 100 per inch,
thats small holes that filter out these gases within the cat, the less holes per inch would mean they are bigger therefor the gase will pass easier, and when you have gases flowing out quicker you will gain more power 😃 😃
although as I think im doubting myself..... :oops: per inch or per cm, either way thats the theary.