Are there torque specifications for the three small screws and lower bolt?I just did this and it was easy to do. Scary in that you have fuel vapors around when it's off.
I jacked up the rear, got underneath and loosened the two clamps (one big hose and one small hose), took off the lower bolt (holds the lower neck to the body), up top - opened up the gas filler and took off the three small bolts, back underneath - pulled off the two hoses (carefully) and then fed out the assembly. The install is the reverse.
My install cured my check engine light (small leak in fuel system yada yada yada).