The rods and crank on the 3.2 i believe are identical.. Either that or i believe the rods are slightly stronger. Depending on your budget you can either rebuild a 3.2 or bore a 3.0.. I, personally, would like to get a 3.0 and bore it out to a 3.2 because if i get it machined, i want to make sure the rings set nicely to the block after getting honed. As far as strength, the 3.0 rods and crank are plenty strong enough to handle a lot of power. i know there are a few people on there making well over 400 WHP on 3.0 rod and crank.. If you do a 3.2 swap, you basically have to use EVERYTHING from the 3.0 other than the short block (block, pistons, rods and crank). But if you bore a 3.0 out, your going to have the same thing.
What exactly are your plans for a rebuild. Like i said, if you want to spend the coin, i would bore out a 3.0 and get all the machine work done to the 3.0.. it should save you a lot of time and frustration in the sense you don't have to keep track of which parts you need to swap over.. If you keep the 3.0 all you have to do is tear down, get machined, rebuild..