I have a Zack tune and I don't know if it needs to be changed a little or if I just need to deal with it because I honestly do not like it. I hate having to decelerate in order for my car to shift from 3rd to overdrive unless I am doing over 60 getting onto the highway. However, if I am not on the highway and speeding up to 45-47ish (around 2000-2100 rpm) then it won't shift to overdrive unless I let off the gas slightly (if I don't let off the gas slightly then it takes about 20 seconds of constant speed to shift). Maybe I am not describing it adequately but you definitely can tell if you are in the car driving or as a passenger.
New DD:
2003 Marauder, Black, all stock except for a tune.