WTF with the 5 x 4 BC and getting axles?

One reason I am staying with the SBP is that I already have some nice wheels/tires and don't want to spend another grand on new wheels and tires. I've heard that it is better to go with new axles if your HP and torque are going to be greater than 350. I'm looking at more than 400 HP out of the engine I have now. If the stockers will work then I may stick with them and save some cash. If I stay with the stock axles which bearings should I use to replace the old ones. The axles I have right now are in pretty good shape.