[ska]

Would he care though?

A good 80% of the people I see riding 3k+ road bikes (in an area that likes to bike, there are lots of them) are carrying far more extra pounds on their bodies than they could ever shave off the bike. It's probably safe to say that the vast majority of people riding bikes have far better bang-for-buck performance improvements available to them than a new bike or components, but don't choose them....

[kevin_thibedeau]

If he's riding in a "fast group" then the weight savings will be worthwhile. You can do this with a used 20 year old aluminum frame. It doesn't take elite hardware to benefit from light weight.

[ska]

If he's keeping up with the fast group already, he may not care (i.e. it's not worthwhile, to him)

I'm not saying you have to spend a lot of money. I'm saying people mostly don't do the obvious performance changes anyway, and for most riders it doesn't really matter (as they aren't doing anything competitive enough to need it).