Driver matching vs break in period


I installed a new mid range driver for my B&W 803 SII and noticed that the image shifted to the speaker with the older driver. I got out my radio shack SLP meter and found that the new mid range driver was about 2-3 DB lower than the old driver in the other speaker. I ended up reinstalling the old driver and putting the new one back in the box. The question is: Is this a matter of matching drivers, or is a matter of allowing the new driver to break in, or is a bad driver? Any thoughts?
koryodell
Here is B&W's response:

"The speakers are all calibrated to a specific spec. Please check the capacitors and resistors on your crossover network. Too often I have seen this open."

Maybe I'll check the crossover values, but I'm not sure why it would be the cross over when the problems follows the driver when I change it to the other speaker.
It sounds like a typical I don't want to be bothered answer.Just give me my paycheck.They used to work with a customer from what I remember.
To check the crossover, do I need to actually get to the resistors, capacitors, etc? Or can I measure the value at the speaker leads and compare it with a new crossover?
To test each component, you need a LCR meter and each component should be removed from the circuit. Before doing that, I would try contacting them again and hope someone else receives your message.