Rear End Swap / Control Arms

I will be swapping my 7.5 rear with an 8.8 w/ 3.73 in the next couple days. The rear and control arms are pretty rusted. Would you suggest replacing the control arms with aftermarket arms or just cleaning them up and replacing the bushings. The under body is also rusted, not any structural damage though. But I plan on cleaning it up with wire brushes then spray some rust killer then undercoat. Does this sound right or is there something else I should do instead. Thanks.

I've had the car for about five years. It's not a daily driver. Weekends and the occasional trip to work. But lately I've become annoyed with the poor ride quality and some other areas which needed attention.. So I replaced the front springs with FMS B springs, replaced the P/S pump and rack. Now I'm working on the rear suspension. I thought now would be the perfect time to upgrade to 3.73, which I here will make great improvement as far as the butt dyno is concerned. I not looking for drag suspension, just a good quality street machine. Ya know incase someone pulls up next to ya. Any suggestion on arms? Thanks.