Going to be doing some general maintenance!

Hey guys, Im going to be doing some general maintenance on my 2003 V6 passat tomorrow because i found myself with a lot of spare time. heres what i plan on doing:

Balance and Rotate
Spark plug change
Possibly seafoam for the first time since my purchase
general cleaning interior and exterior

Does anyone have any suggestions on what else to do? I did an oil change about 3000 miles ago and replaced the air filter at the same time. Does anyone have information on a preferred method of using seafoam on the passat? ( i've done it to past cars but never on a german) Also is there a preferred spark plug to use?

Keep in mind, I have only owned this car for 1 year and have no idea of any maintenance done prior to my purchase.