I agree that you've hit the cheap ones that don't sacrifice drivability. Next you are looking at things like windshield washer bottle, AC, power steering, stereo/amps, etc.
On the other hand, there are also some more expensive ones coming up that also get you hp <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt='

'> OEM Exhaust (manifold & cat back) weighs a TON. S14 alloys are already quite light, so that sucks (for weight reduction <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt='

'>  

. Seats (s14 seats aren't really THAT heavy either). Okay, so maybe 50-75 lbs from exhaust stuff.