The aerodynamics of the car don't "feel" particularly great, so that could contribute to the wandering at high speeds.
EDIT: You also had an older thread about the exact same issue here: http://www.nissanclub.com/forums/201...t-freeway.html
Should probably just continue the discussion there because it does have relevant information.
2013 Altima 2.5 SV
Added: 5000k HID lows; LEDs for license plate, doors, and courtesy lights; Weathertech mats; footwell lighting kit
To-Do list: HID fogs; 30% window tints; LED for glovebox light; debadge trunk; plastidip front and rear chrome trim; smoke tail lights
Last edited by flipn0tic; 01-29-2013 at 06:21 PM.