OUI have traditionally been one of the most litigated criminal cases in MA.  There are a lot of defenses and many cases that do not look winnable can become so.  Do not automatically plead out to your case.  A few things to do are:

1.  Have your attorney file an omnibus discovery motion that includes asking for the officer's training material and notes along with certain certifications and appropriate convictions for subsequent offenses.  Many times you can have the charge reduced- I had a 5th offense reduced to a second a few months ago becuase the DA could not produce the appropriate paperwork which made the offense on that did not have a mandatory jail sentence of 2 1/2 years.  The defendant was told by his prior attorney to plead to a 5th offense. 

2.  Filing pretrial motion to dismiss the case( if appropriate), suppress the stop or speech.  I had a case with a .08 BT dismissed at the pretrial stage this year based on lack of probable cause.  I have had parts of searches, stops and statements suppressed( not be uses against)