That was the first page that came up when I Googled my model #.

I can't find that exact model.
..............................................

Looked some more and found this info:

Model: FR250SDF
Warranty: 5 Years Limited/250k Miles
GTW: 8600
Drill: No
http://www.thehitchstore.com/rear-timbren-suspension-system-p-2512.html

I also emailed Timbren to verify the weight capacity.

Another thought - your truck may be more stiffly sprung than mine. It's suspension is more like a sedan than a truck.

Bottom line?
Timbrens may do exactly what you want/need.

Air bags WILL do what you want/need.

If you take the time it takes, it takes less time.
--Pat Parelli

American by birth; Alaskan by choice.
--ironbender