If the recent results K&N got with the cold air intakes on various Volvos are any indication, then you should go out and get K&N cold air intakes on sale, after selecting the correct model for your car, of course. According to a recent press release from K&N, the company, "has released a high flow cold air intake system (69-9000TS) in powder coated silver for the 2004, 2005 and 2006 Volvo S40 2.5 liter engine and the 2007, 2008 Volvo C30 with a 2.5 liter engine. The C30 is typically found in the European Union. See complete vehicle applications list below. The powder coated silver gives our system an OE look. K&N's air intake system also provides additional performance for the turbo charged engine. K&N dynamometer tests show a 14.61 horsepower gain at 3900 RPM." So what this tells me, is that when I look for cold air intakes on sale, I should try to get a K&N model instead of an AFE cold air intake, an AEM cold air intake, or any other brand. If K&N can get these kinds of results, then that's the brand of cold air filter that I want to install on my car.