According to
Pat Kunz there is a 1% increase in HP for every 5° drop in air intake temperature, due to a cooler lower intake. It's
supposed to be a better performance upgrade than racing stripes, but I personally didn't notice any obvious HP increase.
My STX originally had those big angled stripes on the sides, and I've noticed it's not as quick since they were intact and in good shape. Sadly, they aren't available anymore, so I think I'm going to have somebody paint them back on. That should get me the 5-10% HP loss I've experienced for the last 5 years or so. And along with the 180° thermostat... I'll be "throwing it around a set of curves" like cbxer55! Or I'll throw a rod.