Any advice on upgrading my 2004 Mini Cooper S? I was told I could buy a chip for $300 and upgrade the performance. Does this destroy the MPG and the engine, or is it something rather standard?

 

A chip will dump more fuel in when you are working the motor but should not change your mpg in regular driving. I have one for my 07. If want to get the most bang for your buck the performance pully is the best for your year-more boost go faster. If you do get a chip best to buy any upgrades like air intake and exhust first that way the chip can be set to the upgrades and you will get the most out of it. In my opinion you would do better with a cold air intake and exhaust before a chip because your factory computer will compansate for the increased air.