May I ask why you want to replace your arms with reletively small springs such as the OMEs? The stock arms will flex as good as better than any arm on the market. The only reason to change them would be to adjust your pinion angle which probably isn't necessary with 2.5" springs.
I didn't replace my arms until I went to larger springs. Even with stock arms with my OME kit I was able to pull some real nice flex. I didn't max out the arm travel before I maxed out the spring travel.
The stock arms have amazing flex. They are the best arm design on the market, bar none. It is just too bad DC doesn't make longer (or custom) ones. They have the best of both worlds, awesome flex and low maintenance.