I've been running RS-3s on my C63 for a while now. Currently on my third set
They're amazing tires, very comparable to the AD07s and even the AD08s in the dry. They handle great on the track since they're easy to read and if you do start to slip it's super controllable and correctable. Daily treadwear is decent as well.
Overall a very good alternative to AD08s if you don't want to spend the extra cheddar. But if you don't mind spending the money, I'd still recommend getting the Advans.