hi all i got a 2012 y61 3. l turbo auto its a great car but its very slow off the mark and takes a while to get up to speed i love driving it but feel the power could be so much more it feels restricted i have read about a bigger bore exhaust and diesel chips both expensive to buy and fit and are they worth the money and do they deliver that the makers claim i understand the the partol is set to factory settings. the chip makers claim alsorts of power increases so do the exhaust makers is it best to fit one or the other or both