2004 Nissan Maxima Vibration

When I first took for a road test I noticed shaking and vibration, the dealer said you need new set of tires
I bought 4 Michelen tires and the dealer did a recall on the rear pushings and also informed me that the vibration is because of the suspensions. I changed the front suspensions and I still have vibrartion when I drive on the highway from 50 miles and up.
The vibrartion has been in the seat and I feel it in my legs. The vibration improved a little after all this work and after the dealer did force balance but I still feel the vibration from 50 and up especially when turning left or right. The car is not ver smooth. I did rear alignment only
Could it be that I need to do alignment.
Thank you