the ebay calipers wont fit. the slk55 or clk63 6 pot calipers are the best for the money. i ran them with 18" rims and zero mods except trimming the dust shield. absolute bolt on. the master cylinder is the same for the slk55 and the slk32 so brake bias is perfect. i ran them at the dragon with zero fade.
having said all that the stoptechs are a great setup also and as luck has it all the stoptech parts fit the brembos!!