Siezed pistons on the brake calipers will give you bad vibration and pulling sometimes but you would notice it more when braking. I would have said balance was out too if its while just normal driving. Dont alway trust them to do it right I had to take a car backbonce after it was meant to have been done the front end felt like it was floating around almost un drivable. When I tokk it back they asked if I had hit anything because it was 13% out I never used King's way tyres again.