I don't get the comment to 4... a6 that white should play 5. Nxe5. How is white supposed to continue if black simply recaptures 5... Nxe5 when he is a piece up and also threatening the c4 bishop.
However, I agree that 4... a6? is probably a mistake since fast development is usually top priority in these positions - therefore 4... Nf6 is normal. After 4... a6? one interesting possibility for white could be 5. d4!? sacrificing a pawn to further speed up his development. Since white is better developped already and black is two moves away from castling, it makes sence for white to open up the position like this.
Tell me any improvements!
thanks