tech is right about the mild to wild. it just depends on what you want. they can make a big dif. in the shift. in my younger days I always put the wild and the older I got the milder the kit got. it will help save the clutches in the trans. if you are doing a lot of drag racing. for the old farts GM try to make the trans shift as soft as possible under normal driving, but if you're doing a lot of WOT shifting then you need a kit installed. get somebody that know what he's doing to do it, or you may be walking.