Navistar ( NAV) downgraded at JP Morgan. Rating lowered to Neutral from Overweight. Price target lowered to $47 from $56. 2009 EPS estimates lowered to $2.15 from $3.01. Quanta Services ( PWR) rated new Outperform at RBC Capital. $30 price target. Company should capitalize on the multi-decade capex spending cycle for grid infrastructure. Transocean ( RIG) rated new Perform at Oppenheimer. Sentiment may be more positive than the actual fundamental outlook. Raymond James ( RJF) downgraded at Pali from Buy to Neutral. Valuation call, as the stock is up 40% since June 11. RadioShack ( RSH) upgraded at Morgan Stanley to Overweight from Equal-Weight on wireless stabilization, rent reductions and balance sheet incentives. 2009 and 2010 EPS estimates set at $1.55 and $1.65, respectively. Price target boosted to $21. Starent Networks ( STAR) upgraded at Barclays to Overweight from Equal Weight on signs that healthy demand will fuel solid 2010 growth. 2009 and 2010 EPS estimates set at $0.80 and $0.95, respectively. Price target boosted to $29 from $24. Tiffany ( TIF) upgraded at Credit Suisse to Outperform from Neutral. Price target surged to $45 from $20. 2010 and 2011 EPS estimates increased to $1.83 from $1.57 and to $2.27 from $1.61, respectively Time Warner ( TWX) upgraded at Goldman from Neutral to Conviction Buy. $33.50 price target. Company should benefit from a stronger rebound in national advertising. United Airlines ( UAUA) upgraded at JP Morgan. Rating raised to Overweight from Underweight. Establishes $13 price target. Raises 2009 EPS estimates to -$10.17 from -$12.64.