I am on my second set of RE050A's, they have to be the ADZ compound which is specific to the 'Z' 2007 onwards, the only other car to use this compound is the RX8, sometimes the compound is in short supply from Bridgestone so you have ring around, failing that using the common compound almost nets the same result.
For reference the treadwear on the RE050A's is 140, TOYO's 280 & Falkens 300, now in theory lower the treadwear softer the compound but this sometimes is not nessesary always the case as the tyre wall stiffness also starts coming into play, hence the Bridgestone characteristic of it being low grip when in cold weather but good when it's warm, soft tread but stiffer wall, this is a dry weather tyre first and foremost and to get the best out of any tyre they need heat build up before the grip comes to full par.