Maybe you don't want to hear from the one that sells them and makes the installation parts...This box has evolved into an all brand new box and is even smaller than the 1st gen style. At this point, it's a bolt in and fits 99% of its intended applications without issue. If you have a hemi with 2.25" headers and a Tremec with 8 deg of pinion angle, you may have an issue....The key here is the feel. This box is a little faster ratio than stock and has a sharp on center feel, which is where the oe box falls short every time. I'm sure others will chime in here and there and you'll make a choice that works for you.