A couple of things. First off, all AASPs are REQUIRED by the terms of the contract with Apple to source ALL repair parts from Apple. Now depending on the day of the week and who you talk to, this is either gospel or more of a guideline for preferred behavior. Obviously Apple won't cover parts they didn't sell, so... I don't recall ever seeing any multiple unit packages for HDDs in Apple's parts list when I was doing Apple repair work, so that sounds a bit suspect. The place may do good work, but that buying in bulk should raise a few red flags and you'd be wise to proceed with some caution unless you've dealt with this place in the past and know them to be reputable. In any event, Apple only warrants parts for 90 days itself, so that's a pretty typical warranty period for OEM parts.
The bit regarding proprietary HDDs is kind of misleading, and it's really the fault of a lot of tech news outlets that tend to sensationalize things. So here are the basic facts:
* In the newer 2011-2012 iMacs, the drive itself is a pretty bog standard 3.5" SATA drive, the CABLE used to connect the drive to the MLB is a proprietary concoction of Apple's design, but the drives themselves are pretty bog standard with the only real difference being an Apple logo and SN on the label and a firmware that lets temperature sensor info be passed along to the computer. I don't care how much money Apple makes in a quarter, there's no way to make it cost effective to pay some drive manufacturer to design a custom drive interface for them. They'd hemorrhage money on every iMac sold, and that's just no way to run a business, unless maybe you're making a short-term sacrifice to achieve a long-term goal such as increased market penetration like Microsoft did when they dumped untold millions into Internet Explorer's development. However, given Apple's apparent determination to slowly, but systematically, dismantle their computer business one product line at a time, I don't see that being the case. Oh, and I say that as someone who has actually worked on some of these units. Older models had a special cable dedicated to thermal sensor readings, newer models send it over the SATA cable.
* The only real consequence of using a "non-Apple" drive is that there won't be any temperature sensor readings and it will cause the HDD fan to run at full speed all the time. It'll also throw false-positives if you ever run a diagnostic because that temp sensor will read as anomalous. However, if you can live with some extra white noise, knock yourself out and use whatever drive you want. If you want a longer warranty, ask the repair place about just paying them to put in a drive you supply, and then you can buy a retail drive with a 1 or 2-year warranty.
I have a friend with an iMAC running Snow Leopard. Her computer started acting up, sometimes not booting, so she took it in to the MAC authorized repair shop (out of warranty). They said her hard drive was failing and needed to be replaced. When she questioned them as to the warranty on the new drive, they said that they buy the drives in bulk, and therefore can only give a 90-day warranty (same as all their work). I told her I thought this was wrong, since all new hard drives come with a 1, 2 or sometimes 3-year warranty, and advised her to be wary that she may be getting a used drive.
I was wondering if anyone here has experience with this, or works for an authorized repair shop, and can verify for me that this is standard practice? Thanks!

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