Answer by E. Thompson:
The short answer is Xing Yi Quan. The reason is Xing Yi is a great compliment to any of the long fist, long limb style systems. It is also said that Mantis has its most difficulty dealing with Xing Yi. Xing Yi's thundering, pounding and drilling style movement would be a good compliment to the hooking, trapping and evading techniques of Mantis. Not to mention the difference in footwork and stance-work.