To answer your first question. I think its very likely that their claims are true to a certain extent. Maybe 250m under perfect conditions, but none the less. It probably does have some effect. Weather or not its worth it ??? There are two ways of looking at it. 1) Any single component/gear change that costs extra money will usually give you a relatively small performance difference. i.e From your Sora to your Dura Ace were talking only 0.5 kg lighter. This after spending 15k more and having a big breakfast before riding tends to leave you back where you started in terms of weight. The net effect when looking at any single component/gear change is thus usually negligible and you will hardly notice it. 2) Following on from (1). If you now go and upgrade a hole lot of components/gear. Lets say Alu to Carbon frame = 1kg, Lighter wheels = 0.5 kg, Top groupo = 0.5 kg, fancy new Prevail helmet = ? kg, etc, etc you could find your self with a bike that may weigh 3 or even 4 kg lighter and no more money to eat a big breakfast before the ride. So the net effect now is much more substantial and you will notice it, but so will you bank manager. So, my thoughts is one sentence. Like we used to say at Tukkies. "Gaan groot of gaan huis toe !!!"
