The Langsters are very light, are very well made and strong (you also get carbon forks which take some of the road buzz out of the bars). You can get gel grip tape to make the bars even more comfortable if u ever find it too hard.

58cm is probably too big, although they have compact geometries and you might be able to get away with it (unlikely though.)

I have a Bianchi Pista (Jpn edition, which is different to the rest of the world for some wierd reason). It also is light, but the components are a bit lower quality (truvative touro compared to the Shimano Sugino on the Langsters).

But make sure you get a bike that fits, you want a 54cm really, you might be ok on a 56cm frame though, you can go to a good bike shop and get them to measure you up.