Steering wheel vibration

Talked to service mgr, nissan consumer affairs, shop foreman, all say this is characteristic of 2010 altima. (I test drove several 2010s and did notice this but tried 2011 altima - no steering wheel vibration. Something either changed or a part that was not meeting specs, now does. Nissan will not tell me what they changed nor give me a clue what to change with my own $$$. Willing to pay to get it fixed, do not want to take $$$bath on trading in for 2011. Did notice the vibration is worse on new flat roads versus worn in roads - maybe something is not holding tires to road properly? Also, seems to be speed sensitive - occurs at around 40 slightly and increases to unacceptable at around 68mph. Same in Neutral gear. Wheels have been road force balanced according to service mgr, but I don't trust anything they say anymore bc I had to since replace 2 defective tires and they won't switch out the parts from a 2011 to find out for their own knowledge and my fix?

Wheel alignment was done when 2 new tires were put on front. Mich. Harmony on front and mich mxv on back. When you say identical, they may look like the same parts, but do they meet the same specs? I have heard no problems from 2009 and several from 2010 owners on net and in person.