I've been trying to do a weight concious build, and am trying to get to 2300 lbs dry weight. Lots of little things like a 14 lb flywheel, a 15 lb battery, lightweight
oil lines, etc. plus the obvious ones- all aluminum FE, G-force T-5 instead of the toploader or TKO, Quicktime bellhousing, light weight starter etc. all add up to a significant savings. The next one I'm thinking about is magnesium wheels. About a 70-80 lb total weight savings and its unsprung weight to boot.
From the get go, I was trying to get to a power to weight ratio similar to the Indy lights cars I drove (1400 lb/450hp). Its not really possible, but I won't be that far off (2300lb/600hp). Those cars were so quick, particularly when set up in street racing (Long Beach, Toronto, Vancouver, Detroit) mode. They were all carbon fiber except the few suspension bits and the drivetrain. Light weight is a greater benefit than just putting in more and more HP. The cars turn, stop and of course, go better and are more fun to drive.