NEW YORK (Standard&Poor's) Feb. 4, 2008—Standard&Poor's Ratings Services said today that its ratings and outlook on Sprint Nextel Corp. will not be affected by the company's requirement to record an impairment charge related to the book value of its core wireless unit. Sprint Nextel said in a recent 8K filing that this non-cash charge is a goodwill write-down that will be substantial and could potentially amount to the entire $31 billion of goodwill recorded on its balance sheet. Standard&Poor's lowered its ratings on the company to BBB-/Negative/A-3 from BBB/Watch Neg/A-3 on Jan. 22, 2008 due to the loss of postpaid wireless subscribers resulting from operational and marketing problems that have plagued the company since