I am not quite sure where this post goes so please move it if necessary.

I just got new tires and have had them balanced (twice) in the past 30 days. The tires I replaced were very used so I thought they were the problem. Now that I have BRAND new tires and the tire company swears they are balanced, I am trying to figure out why I still have a vibration.

The vibration seems to be there on acceleration, deceleration and coasting. You can start feeling it around 20 mph. There are two roads I drive daily that have been repaved in the last 6 months so I KNOW the roads are very good.

Any ideas on what to check? Could it be driveline, suspension???

PS. My stock shocks have been replaced with Bilsteins in the last 20 months.

When my injectors were putting too much fuel into the cylinders I got a horrible vibration. The only other vibration I can think of would come from u-joints being out.

IF you were having vibration issues before you changed tires, and you still have it, then it is not the tires, it has to be something else. You could have a bent wheel, or some driveline issues. Have you or anyone else jumped a curb or anything that might have tweaked a wheel? I suppose it could be your driveshaft is out of balance or something else.
I would recommend a road force balance on the tires. that would find a bent rim

Can any tire shop do a road force balance, or do I need to go somewhere special for this?