you need new muffler bearings and some turbo belts.

edit: on a more serious note...can you get ahold of a different boost or vaccuum gauge and test it independently...maybe your boost gauge is fawked up....also I know your turbo was sounding a little less than full on when we were hangin out...could you have finally fried it? Also doesnt your ECU crank down the boost when it is super cold out..could it crank it down more and more as it gets colder?