I have 98 Civic Coupe with stock (D16Y8?) engine and manual transmission. I was thinking about adding some power to it and maybe some more sport-like "engine noise" so I was looking over ebay for some staff for it and i want to ask you guys if those things are really working, and in what way (better or worse). I'm talking about HiFlow Cat Converter and Cold Air Intake filter.

Here is some examples of what i'm talking about.
http://cgi.ebay.com/ebaymotors/CIVIC...spagenameZWDVW
http://cgi.ebay.com/ebaymotors/Honda...spagenameZWDVW