i heard about a style called Sum Yi does it exsist and what has it incommon with Xing yi

"Sum Yi" is the Cantonese pronunciation of "Xin Yi." Xin (heart or mind) Yi(intent) is an older name of what is popularly called Xing (form) Yi (intent)today

While Xinyi is often said to be an old name of Xingyi, the fact is that actually Xinyi is a separate style with distinctive features, and is still practiced nowadays (in two main branches - Dai Family Xinyi in Shanxi and Henan Xinyi Liuhe Quan). Xingyi evolved from Xinyi and while carrying some similarities to its "father", it has developed its own set of practice methods and techniques.

Just like anything Jarek, what was Xinyi (probably came from Honan) as this is the older of the three newer Xing Yi styles. Next Shan Xi and then Hebei.

I also think that if you asked any old man practicing in the ROC between Xin Yi or Xing Yi, he'd look at you like you were a frickin kook.

Practice hard and frickin sweat historian boy.