We are looking at a used 36 Outlaw with 496's and extension boxes. What would be the advantage of the boxes on this setup? Any disadvantages? Any input is appreciated.

On plane quicker with less tab angle..Better drive positioning as far as x dimension.Better handling,acts like it a longer boat...What year is this Boat??

2001

IF the drives are up high enough it will gain all of the above plus better speed & ride ride quality compared to an equal 36 without boxes.
If the drives are deep (deeper than 4" below the bottom of the boat) you will only gain ride quality & you might be as fast as an equally equipped, minus boxes 36.
In any case, I would opt for the one with boxes. You can pick up some -2" Imco lowers & you're on your way to better speed without having to do engine work.

+1

That year.... I'd bet they're deep