Hey guy here are my two cents. My 400 E also starts in 1. On this site there is a thread that explains the component in the transmission that controls this and how to alter it if you want. As far as the slow start I have found that if I hit the gas from a dead start the initial preformance is a little sluggish but if I hit the gas ALL the way to the floor including depressing the kickdown switch I burn the tires off in a way not for the faint of heart. Maybe the switch tels the computer a few things about air fuel demand/mix under Full demand instead of the tps communicating throttle position. Don't know just glad it does.

Take care
Brian