Fall is the perfect time to encourage your clients to go for an extreme change. That's what Brittany Harder, a cosmetology student at Tricoci University of Beauty Culture in Rockford, IL, did for her friend (and fellow cosmetology student) Cara Ballard, taking her from a faded blonde to a vibrant, va-va-voom red. Inspired by Paul Mitchell's Flame Red step-by-step, that was featured in Behindthechair.com On Paper, Brittany and Cara created their own version using Redken color. Together, they came up with a formula to take Cara from faded to ravishing with her…