well the car is a daily driver and i rarely go to the track but when i do and want to do some hard launching i dont want to worry about breaking something and the car is N/A and i dont plan on any big power adder except maybe nitrous someday. so if i put the 28 spline locker in it should be fine since im not doing hard lauches that much. and also what rpm would be safe to launch at with slicks on the 28 spline.