Here's some considerations about classical guitar and Fernando Sor :
learning 'Studies' and '120 Arpeggios' by Mauro Giuliani is very useful for the right hand technique
but, playing Fernando Sor studies or compositions, is useful to play everything good.
If you study a piece composed by Carcassi you enter the Carcassi world of composition and
when you play another piece by Carcassi it will be easier.
This is the rule for all composers : they teach to play their own style.
But Sor is different. Sor improves the way you play every age and every style.
Sor was a genius and his friend Aguado had understood this well.
If you want to play well on Ponce, Castelnuovo-Tedesco, Gilardino, Carulli, Tarrega, Villa-Lobos or other composers first you have to play Sor.
Fernando Sor - Andante Largo played by Daniele Magli