i have an 03 edge, im wondering how long and hard would it be to drop in a roush or svt v8 in there

If you are talking about the 4.6L V8, it does take a while for the swap and it is more difficult than a 5.0 swap. The easiest Rangers to do that swap in are the '98-up 2wd with coil springs in the front. They have a wider frame up front than the 4x4/torsion bar frames. You would have to make your own motor mounts and headers, modify the HVAC box and steering shaft, and be able to do some major (to some people) wiring.