I have an XH ute which as we all know has very little space for speakers/subs etc. Currently I have Rockford Fosgate 6" speakers in the doors and they do the job, but I was hoping for a bit more. While I've seen some mods to the rear wall, I don't want to go down that route and I've thought of two options. I'm keen for advice as to which might be the way to go.

A) A powered slim sub under the seat like a Fusion 8"
B) An amp (if needed) and 6x9s (I saw them on Fordmods in small boxes that fitted behind the seats)

Like everything with this ute I'm trying to keep the cost down, but up to about $400 max would be perfect.

If your looking for mid bass I would use a amp on the 6", not knowing what Rockford fosgate rang you have makes it a little difficult, I've used fusion power plant component speakers before. Nice mid bass good money for value