I think he is saying that his Evo doesn't feel twitchy even with just a 5mm cap under the stem. Most Cannondales come with a 25mm conical cap and a few other spacers. That set up is fine (for me) on my CAAD10 - but I traded out the 25mm for a 5mm on my Syanpse to get my hands lower (and my position is 'fairly' similar on both bikes now).