This often crosses my mind (good thread Sam).
In no particular order I have previously thought about the following vague headings. Trouble is most of them I have ruled out as being too expensive or having too little real impact or otherwise ruining the nice bits of the car. If you were making a track car though things might be different
1) Sort out the junk you carry around. I reckon I have a good 10kg of stuff that gets lugged about everyday, spare oil, roadmaps, owners manual, emergency raincoat etc. Thing is I carry most of it for a reason so probably wouldn't want to take that out. You could drive in the nude through.
2) Strip the interior/luxuries. You could lose some serious weight here - stereo, aircon, comfy seats, electric windows - but would you really want to?
3) Other mods that lose weight as a bonus. Decat manifolds and other exhaust bits are probably the most obvious but I guess other bits may shave a few grams - carbon plenum and intake pipe
4) Lighter wheels. Probably not an option for you with your lovely CHs or anyone else that likes their teledials/multispokes but you could probably get a few kgs off if you chose a set of rims based on weight - eg Oz Alleggerita.
5) Lighter brakes. Alloy bells and rotors have been discussed on here before. Would be an expensive option but may take a bit of weight off.
6) Carbon or aluminium body panels. Mega expensive (eg http://www.absmotorsport.net/alfa/14...re-bonnet.html
) but I suppose it could make sense if you're a 156 owner replacing rusty wings and you could find someone to build some aluminium or carbon replacements. Not aware that anyone does this at the moment, although I've always thought that Alfaholics could look into it as they do similar for their Gta replicas.
7) Moving the battery to the boot. Not a weight saving as such but better weight distribution and done by a few people already.
8) De-badge it