I finally got a half decent response from a WD rep.
WD Rep wrote:
I have double checked with our engineers and although your tests are showing a performance delta on the replacement drive that was sent to you the Performance specifications are the same. All WD3200AAKS drives are designed and built the same. The sub number after the dash is a reference number that is the first part of an extended number within the drive, that is used for internal purposes only, indicating what components and firmware is used on a particular drive
Now, I'm not sure who to believe. If both drives are the same, why is the B3 revision faster and quieter? Why are the drives' casings different if the same number of platters remains the same? On one hand I have info from WD and in the other, I have lots of solid data that directly and conclusively contradicts WD.
I responded asking if I RMA my replacement drive (the 00VYA0) can they guarantee they'll send me a B3.
That is a plain straight out lie.
00VYA0 = 2 platters
00B3A0 = 1 platter
There is no way that differing number of platters satisfies the All WD3200AAKS drives are designed and built the same
Now it may be that some rep in a call center just turned to the guy/gal next to them and asked what to say and you got a bogus answer without intent to lie but no matter the intent the answer was wrong.
If they didn't replace your RMA drive with a single platter version after you sent them a single platter version. I'd suggest you take all your documentation of the incident and send it to firstname.lastname@example.org
with a plea for help at the bottom. Once it gets posted there hopefully someone will respond from higher up the food chain at WDC. The consumerist crowd might help you get contact info for someone higher up to get the issue resolved to your satisfaction and it might take another email or call but you deserve better than a crappy part swapped old hard drive.
As it is WDC has lost the purchases they would have gotten from me if the 320GB single platter drive had a part number that differed enough an online retailer would keep it separate from the 2 platter version. I don't know an exact number but it's at least 3 hard drives I would have bought for myself plus any I might have bought for work.
I have no interest in replacing 160GB single platter drives at work with 320GB dual platter drives. I don't need the space, I do want the speed.
I still recommend the 640GB Blue and Black but I won't look back when I start buying SSDs. I won't have any remorse if WDC pulls a circuit city by giving their customers poor service/support.