According to the owner's manual (including the ST supplement), no break-in period is required.
I find it hard to break old habits, so despite the manual, for the first 1000 miles, I do the normal break-in thing:
- vary the RPM (not necessarily "speed"; if you're on the highway, move between upper gears occasionally to vary RPM even if you're stuck at 65 mph)
- avoid high RPM at first (hard as that is with an ST :)) and only gradually increase the upper bound
- make sure the engine sees at least some instances of high pressure (open throttle in a higher gear will do this without necessarily causing a lot of acceleration, RPM, or speed)
- make sure to decelerate under vacuum as well (leave the car in gear and take your foot off the gas when approaching a stop, etc).
Change the oil and filter after 1000 miles.