there are different versions. My knowledge isnt the best but PF48s were the originals. They upgraded to PF48Es which I guess have better internal material and recently they went to PF48R which are supposed to be the best but cost more. They are heavier, people say they help resolve some low oil pressure issues, not sure how but I needed one I could get locally or fast online and didnt want to dummy mission multiple stores. I ended up getting a PF48r which can be shipped by tomorrow. Only reason I went this route is speed of shipping. The PF48e never failed me. If I come back with oil sensor issues or worst, you know why LOL.