Okay-
Found this @ ToyotaNation:
First - someone who works at a dealership says you don't need to replace them (filters) and the dealer does not even stock them.
Uhmmm I don't think so......
This following info looks good - NOTE : because there is 'goo' for a gasket you probably need to be carefull (add more goo?) reassembling to keep a tight seal since the system is pressurized !
Second - someone with common sense-
I replaced the Highlander fuel filter on my 2003 4 cylinder with ~30K miles. You only have to remove the left rear seat to gain access to the fuel filter/pump inspection plate in spite of what the shop manual says.... Do this in a well ventilated area with no combustibles about. To remove the seat you have to gently pry up the forward edge of the
cargo floor, pop off the seat back bottom carpet, unbolt the seat ( 4 bolts ) & peel up the left hand rear carpet . Lift out the circular plate with the wire harness running through the center. It is held in place with some black goo. Next unhook the fuel line using your fingers ( no tools ) and unplug the wiring connector after releasing it at the forward side with screwdriver. Mark the orientation of the assembly as it sits in the tank. Then unscrew the attaching bolts ( 8mm or 5/16 ) and gently draw out the fuel sender/pump/filter assembly. You'll have to disconnect a rubber hose before the assembly is free of the car. Swap the parts onto the new filter & reinstall everything.