Standard&Poor's Ratings Services lowered its Standard&Poor's underlying rating (SPUR) on Fitchburg, Mass.' GO debt two notches to 'BBB-' from 'BBB+'. The outlook is negative. The downgrade reflects the city's: Weak financial position, Absence of clear efforts to achieve structural balance and restore the financial position, and Limited local economy. The city's low overall net debt position and recent property tax base growth are offsetting credit strengths. The city's full faith and credit GO pledge secures the bonds. Fitchburg, with a current estimated population of 39,910, is 46 miles northwest of Boston, Mass. and 25 miles north of Worcester, Mass. The city's financial position is weak, and officials expect it to continue to decline at least through