I've got them on my x-cab tacoma with 6 foot bed and bed xtender -- with a narrow truck box preventing me from placing the front rack directly behind the cab, I had to modify the front rack to accommodate the wheel well when the rack is in a lower position -- important -- DON'T saw the rack off.  This will prevent you from being able to raise the rack above the level of the cab to carry canoes, 16 foot boards, etc.  The vertical rack posts are double walled.  I carefully machined middle notches creating a middle height for the racks that is below the cab but avoids hitting that wheel well.  I used a dremel, a sawzaw, and some hand tools and took my time.  It didn't compromise the integrity of the racks because of the double wall.

Btw -- I got my whole set of racks for $250 from backcountry.com.  an amazing deal -- it's half off sticker.  I don't work them -- just sharing my experience.

Mike