almost ready for the V

Well finally have enough to get a ats v. looking for a sedan but am oen to a coupe for the right deal. Also want a 8speed but open to a 6speed for the right deal. Want a red but open to other colors if the right deal. Budget id 35k but can go a little more for the right car (low miles) . I heard about the wastegate chatter thing but will read more on it. My only serious question is on gearing 8speed vs 6speed as in Florida we mostly have flat straight aways any differance in top speed or 100+ to top end . Like is the 8speed geared for better acceleration but the 6speed has more top end ? Any help would be appreciated