I guess your driller just prefers Berkley pumps. The pumps and motors come separated anyways that big so it's no big deal to use your motor of choice and Franklin is top notch. Since you have blown two pumps and a c-box I suspect that your well/tank is getting waterlogged and you're not catching it in time. Do you know if you have an air-maker/bleeder system? You need to be checking the snifter valve every month to make sure that it's not plugged.
I don't know anything about the water worker tank. Some people claim it's the same tank and some claim that it's not made quite as well as the normal WXT. I tend to think it's probably made a little cheaper, hence the shorter warranty. You don't need to move any of your pressure switches or anything like that.
Good luck to you and make sure you post up what the results were. I would like for you to time the pump run time before/after and let us know the difference too. I think you'll be pleasantly surprised.
For even better results use an air compressor and add an extra bit of air to your tank than the natural drawdown. You can get your galv. tank to a charged state where you can have a 50-gallon drawdown just by adding air via an air compressor.