The possiblities are really endless. First you need to try and isolate the problem, when does this occur, etc.?
When you bought the new tires for the car, it should have came with a lifetime balance of tires for free, if you go to NTB, you can get a free estimate for 4 wheel alighment.
If you have a bad engine or tranny mount, then it could cause vibrations. Best way to tell is get the car in the air and look at it.
A bad spark plug can cause one of the cylinder to not fire properly and cause vibs too.
Does this happen ONLY when you accelerate? could be fuel related.
I hope this helps.