Any model Spinergys versus 303 tubulars is about 1.5 pounds. Not to mention the use of STI shifters AND aerobars.
If you look at my build kit...Ritchey WCS stem is one of the lightest stems, Hed fliplites are the lightest aerobars, Selle Italia SLK is a light saddle, Zipp 303s are out of this world light, my new crank is another 100-150 grams lighter than most.
Don't sweat the weight. I do it for fun, it really does very little for speed and because when I spend my money I get something that stands out. Really, I'm trying to track down a disc(HINT HINT IF ANYONE HAS GOT A 650 shimano disc they want to get rid of CHEAP) right now and will gladly take the extra pound.
Upgrades have been put on hold for other much better invested dollars however...