PMF traction bars

[slim!]

I've done a bit of searching and haven't been able to find what I'm looking for.
On their site they list a few different types of axle mount types. The ones that interest me are the bottom nut u bolt plate mount and standard bolt on.
Do these just replace your current plate on the bottom of your axle and what's the difference between the two? I've been looking for pictures but the pics on their site are pretty small.
Also, where it mounts on the frame, I noticed that my skid plate for my fuel tank is in the way (I would assume?) does this get removed? or do they mount on the side of the frame like OUO? The first pic on their site has me thinking otherwise.
Thanks for your help guys.

Bars I'm referring to - http://www.pmfsuspension.com/1999-16-Ford-F-250350-PMF-Single-Traction-Bar-Kit_p_21.html

 

[sootie]

Yes they replace the bottom u-bolt plate.
they mount to the bottom of the frame rail with a tab that goes up the outside of the frame rail. Two bolts from the bottom, two from the outside.

i ditched the fuel tank skid plate iirc...

 

[slim!]

Perfect, that's what I needed to know.

Do we have any vendors on here that sell them or should I go direct?

 

[sootie]

PMF is a vendor here. Trevors handle is NotStock.