I got a 2011 lexus ES350, the steering wheel shakes badly when i push the brake. I have been told that its the rotors. I got the rotors resurfaced last week at the lexus service center but no improvement. Plus the brake pedal is now set lower and i have to apply more pressure when braking. Should i just get new rotors? Does this shaking cause problems is other parts of the vehicle?
Your initial symptoms do indeed point to an issue with the brake rotors, but given that resurfacing did not address the issue, it is possible that you have an issue with uneven tire wear or wheels in need of balancing (that or they did a really lousy job of resurfacing the rotors).
As to the brakes requiring more pedal effort after the service, this may be a temporary condition as the brake pads and rotors once again "bed in" with one another. If it is not a dramatic condition, you may wish to wait and see if it improves. If it is a dramatic condition, get the car looked at again as soon as possible.
As to your comment that the brake pedal is "set lower", this is strange to me. Hydraulic disc brakes should be basically self-adjusting, and should always engage in roughly the same place.
This vibration is not likely to cause any issues in other parts of the vehicle, however, a driver of such a vehicle may consciously or sub-consciously make changes to his or her driving behaviors as a result of the vibration, and this may create a dangerous situation.
Regardless, if you paid the Lexus service center to address vibration under braking and the problem is not resolved, bring the vehicle back until it is!
Brake rotors do not "warp"; it is a myth. Surface irregularities can occur due to factors such as overheating and can be corrected by resurfacing the rotors on a lathe. It is unlikely that one or two resurfacing operations will affect thermal characteristics but the condition causing the vibration may reoccur within a short period of time. Without other unidentified causes it may be necessary to replace the rotors. If neither resurfacing nor replacement eliminate the vibration, it is obviously something else.