I need some help installing this. The oem overflow tank only had two hose fittings and the small overflow hose. The mazsport tank has two hose fittings on the bottom and one more in the upper tank along with the overflow on the filler neck. Which fittings do the upper and lower hose on the oem tank match up to and what is the third hose fitting for?

 

just guessing here - third hose is for turbo supply or return line ?????