Engines are identical except for the the header because of the ATTS unit which is what makes it an Sh. I dont want to get to drawn out on how it works but simply put it lets you handle like a mofo. But it gets less to the wheels than the base and is heavier. If you want a track car get the Sh, if you want a drag car get the base, but only get the base if its a manual. Ive heard bad things about the Sport Shift thingy. The only draw back to getting the base is it has uglier rims, usually no wing, but worst of all it has gray trim along the bottom including on the rear bumper. I would suggest the base if you just want a "race car" but I would definatly get rims, an OEM wing, and have the trim painted, but again only get the base if its a manual. The low milage on the one your looking at is a good sale point too. Bottom line, if its a 5-speed then the base is definatly the better deal. Hope this info was helpful for you.