Got a couple of new ContiTube Race 28 butyl tubes in the mail so I thought I'd throw them on the scale
Continental ContiTube Race 28 (700C) 700x20-25c, 60mm Presta (threaded) ... 104 grams
Continental ContiTube Race 28 (700C) Light 700x20-25c, 80mm Presta (non-threaded) ... 79 grams
Pretty big difference. I thought the 20mm longer stem would have added a fair big of weight, but there's a huge difference in the wall thickness between the Race 28 and the Race 28 Light as you can see in the photo. I'll probably put in the heavier tubes anyway for the added puncture protection, at least for now.