Most of the time, telling the officer that you do not want to perform any tests on the advice of your attorney is your best bet. If you refuse to perform any field sobriety tests the prosecution is not allowed to introduce evidence of that refusal to a jury. The reason the officer asks you to perform the field sobriety tests is so he can use the evidence against you in court. Officers are also often not well trained in performing these tests and frequently make mistakes which seriously calls into question any scientific validity that they may have. So even if you actually do pretty well, or there are good reasons why you failed, you are still likely to get arrested.