Is it true that shielded cable rob some amount of life and speed from the music ?
Shielding can raise the capacitance, which can decrease bandwidth and therefore speed (resolutIon) somewhat, but it also depends on the implementation. Kimber, for example, achieves high noise rejection while keeping capacitance low with their woven cable techniques. This is also true of Shunyata Research. A third way to shield is to have more space between the conductor and the shield, making for fatter cable.
You probably want to keep this cable's total capacitance at 100 pF or lower. AudioQuest manages to have solid conductors, shielding, and pretty low (sometimes very low) capacitance. Their Angel interconnect might be a good candidate, but I don't know its capacitance. Conductors are highly polished solid core silver, which has 8% more inherent conductivity than copper.