You probably wouldn't pay $6 for an iPhone app that lets you browse through car models and pump stereo exhaust sounds directly to your drums. But a $6 Aston Martin Experience app that also displays speed and Gs as you film your drive from behind the wheel of a 2011 Rapide? We might be in love. The British automaker's latest app can do all of the above, and also includes a list of "top roads" -- most of which are in Europe. Our friends at Autoblog paired the app with a loaner Rapide (and we thought playing with cell phones was cool), driving up California's Aston-approved Pacific Coast Highway. The reviewers may have spent more