i'm about to trim my floor pan so my seats fit better in my 34 cabriolet kit car. might as well do it once so i want to incorporate the opening for a shifter. my question is, what shifter can i use with the 4L60E? i don't necessarily want to use an aftermarket, i like several OEM shifters. what does this tranny require from a shifter? I like to have a manual shift option.