Congratulations Luca, let's see some pics of your Birdy. New, used, good deal?

I think with any bike the tires, saddle, seatpost, and handlebars are the biggest easy weight loss. A lot of people seem to have problems getting carbon fiber seatposts to not slip because they can't be clamped tight like metal seatposts. I personally tend to increase weight with my saddles because Sella Anatomica and Brooks weigh a lot but are comfy. So I would start with a carbon handlebar, lighter tires, then maybe pedals. An expensive drop in weight would be the new Sram Dub crankset but I don't think they are for sale yet.