I would love to be corrected, but I was under the impression if you refused any testing, your driving license will be revoked. Drivers license is a privilege, not a right.
If the police decide to have you exit the car and do the field tests, the odds are high they have already decided to arrest you. At that point, it's best to refuse all unless you have had absolutely zero drugs/alcohol. And then the question has to be why did they have you get out the car.