I searched the PDF of the Owner's Manual and found nothing on brake pad thickness service limits. When do the brake pads need to be replaced? How thick? I'm at 7 mm Front and 3 mm Rear. Seems like the Rear might be in need of replacement. Also, while we're on the topic, is there a thread here that covers common replacement brands that are equivalent to OEM quality as well as upgrade quality? I'm not too keen on changing to a harder pad material, but I am curious to know about options. Ideally, I'd replace my brake pads with the equivalent of what Tesla Motors would be using if I took my Roadster to them for a simple brake pad replacement service (except for the price - they quoted over $1,000 when they gave me the thickness measurements above).