if i wanted a lightweight clutch kit would I be going mad?

wondering how much of a weight savings there would be and which clutch kit would be best for mostly street use?

I know that the stock one is perfectly fine, and I don't need to replace mine any time soon. I'm just curious because I like to know these things.

I see a STM Evoluzione Alloy clutch group here that replaces the 6 OEM helicoil springs for a 90mm Evoluzione diaphragm spring....what are the specific benefits to doing this? Any negatives?

Also, what's the difference between the 12 tooth and a 48 tooth? One for the sbks and one for the rest of em? Any info would be appreciated!

Also, on the slave cylinders....I see an option here for a 28mm and a 30mm, what's the difference and what bike gets which size?