do they really have any beneficial aspects for the engine besides it running cooler? is there any noticeable horsepower? or do people just buy this stuff because its mugen? because if there are any gains that are worth it, then i wouldnt mind picking it up for my rsx....

 

Some people reported bad gas mileage because the car would not get warm enough during every day driving. Search the archives.

If I really felt I needed it, I personally would just go to autozone and buy a colder thermostat and a fan switch with a lower temp setting or is adjustable. It would be much cheaper.