I love my Dinan. Warranty is a non-issue, install was cheap at a non-BMW location, proven gains...no downside!
And to answer the next question, no problems with AC, engine cooling, hard steering feel, etc, even at a track...albeit in SoCal.
2014 Porsche 911 Turbo S - FOR SALE
2010 BMW M3 (e90) - SOLD
2005 Corvette C6 - SOLD