I am not sure if I have the right BPV. I purchased a Wildwood BPV with one line in and one line out. My friend tells me I need one with 2 lines in and 1 line out. Is this correct? From what I have read the BPV goes in the engine compartment and not in the rear where the stock one is. So how does this all work? Can someone fill me in please?

Your friend is wrong. You only need two ports; one in and one out. There are two lines going to the rear brakes on a stock 4runner. One of these lines is a bleed-back for excess pressure to be bled into the front brakes. You can cap/remove this line as you do NOT need it with a BPV. Plumb the line coming from the master cylinder to the rear brakes into the "IN" port on the BPV and the line from the brakes into the "OUT" port, then adjust as necessary.

Anyone have a picture of their BPV installed?