The DCT N54 does not allow launching in 2nd. You have to launch in 1st and yes the gearing is different from the regular N54.
All 200+ launches that I have done were all in 1st gear with a best 60' of 1.84
Keep in mind the DCT N54 does not have a torque converter
BQ Tuning by WedgePerformance - Torque Junkies
DCT 335is 121-122 mph in the 1/4 mile Stock Turbos / Full Weight