rear axles

I was wondering if it would be better to build my 8.8 31 spline up stronger or just swap it out to a ford 9 inch, what would be more cost effective for hp rating?

im in need of a rear axle on the western slope of Colorado. 07 ranger 4x4. 3:73 ratio 8.8 ring gear, 10 inch drum brakes. Would also be interested in part trucks or builders. 96 and or 2007