Im seeing the same thing, sport mode, and its reving around 3000 rpm, and doesnt shift down. Im going in friday for a computer update, which i believe is part of the transmision tuning they said they would do on the SX turbo with the dual clutch transmision. Ill let you know after i get it done Friday if it changed that behaviour or not.
I went in for the update to the cars computer system, and it runs like a dream now, no overreving at the 3000rpm mark, and the turbo is much smoother, the hesitation taking off is gone, so i would recomend this update to anyone with the 1.6 litre Turbo and dual clutch transmision. Just call your dealer and ask about it.