Car and bike parts retailer Halfords was the best performing stock on the FTSE 250 on Friday after UBS raised its recommendation for the stock by two notches from 'sell' to 'buy' and hiked its target price from 280p to 375p. "Halfords is a brand with high market share in its core markets, good resonance with consumers, and finally is undertaking some of the investment required to succeed as a specialist retailer," the broker said.In contrast, homebuilder Persimmon fell sharply after UBS cut the stock from 'buy' to 'neutral' on valuation grounds, saying that the stock is "now almost priced to perfection".Platinum miner Lonmin surged as negotiations continue with labour unions in South Africa. The stock was given a boost this morning by Morgan Stanley which upgraded its rating from 'equal weight' to 'overweight', saying that the shares appear attractively valued versus peers.Mining stocks in general were in demand today with Petropavlovsk, New World Resources and Hochschild Mining all making decent gains.FTSE 250 - RisersHalfords Group (HFD) 335.30p +8.16%Lonmin (LMI) 300.80p +4.81%New World Resources A Shares (NWR) 103.70p +4.43%Petropavlovsk (POG) 141.30p +4.36%Synthomer (SYNT) 203.40p +2.52%Keller Group (KLR) 949.50p +2.15%RPS Group (RPS) 212.50p +1.87%Hochschild Mining (HOC) 258.00p +1.82%Anite (AIE) 129.30p +1.73%Thomas Cook Group (TCG) 148.50p +1.57%FTSE 250 - FallersMan Group (EMG) 116.80p -4.34%Perform Group (PER) 558.50p -4.04%Persimmon (PSN) 1,179.00p -3.76%Mondi (MNDI) 870.50p -3.49%Investec (INVP) 455.40p -3.25%Imagination Technologies Group (IMG) 356.20p -3.21%Howden Joinery Group (HWDN) 234.90p -2.77%Cobham (COB) 285.30p -2.76%JPMorgan Indian Inv Trust (JII) 383.00p -2.72%Taylor Wimpey (TW.) 98.20p -2.58%