Vibration

Last week I had the timing belt replaced (preventative maintenance) and new front brake pads. I immediately noticed a vibration when I left the shop. I called and they asked me to bring it back the next working day. The vibration was so bad the next day that it was making my side mirrors and rear view mirror "blurry". They drive it. It appears fine to them. I still feel a strong vibration in the steering wheel. Actually all over but it's worse there. My question is: I don't know what repair may have caused the vibration and what to insist they look at when I go back! Is it the timing belt replacement or brake/rotor? It had no issues at all when I took it in for maintenance.