BMW Offers Performance Power Kits
BMW is offering two "Performance Power Kits" for its 135i and 335i models. The software upgrade reprograms the engine control chip to boost output by 20 horsepower to 320 horsepower. The kit starts at $599 and does not include installation. It's also available as a retrofit on BMW X6 models built through April 2010. A second kit, with a list price of $1,199, includes the software and some hardware, including an auxiliary water cooler and a beefed up radiator fan to handle the additional heat on the engine during extreme driving.