yea suss makes a good point. if you really can't stand the dct then trade in for a manual - no need to upgrade to ST.
also... have you tried taking your car into the dealership? It might just need an update and/or quick fix... I had a little bit of issues but the trans is fixed and computer updated and the car is great now! It's under warranty so just go take it into the dealership and get it fixed before you make such a big decision. A lot of the problems are solved by simple computer update.
hope this helps
~ Shadowfax ~ 169.5 whp; 156.5 torque