the spring really is a personal preference.ive had it in and out and the install is fine either way.i personally think shifting is easier for me without the spring,but ive never put a clock on it and tried to record the shifts and even if it does help its so small its prolly' not even noticable.as long as your hitting the gears properly it shouldnt really make a difference.

(2)1994 mustang GTs 2001 gt convertible loaded.www.haywoodspeed.com