what tool do I need to change filter?

There is a pair of plastic tools that you force into the small space between the fuel line and the filter inlet and outlet ports. these plastic tools will spread the metal tangs (fingers) that are gripping a ridge on the end of the fuel lines. The cost for the pair of tools is about $5.50, but you can not get the filter off without them, unless you are willing to cut the fuel lines and replace the cut portions with hoses -- which will cost about the same as buying the tools.