I'm on the verge of upgrading my mid 2009 2.5GHz 15" MBP to one of the late 2011 MBPs. I know this might sound daft but are there any known issues with aftermarket memory, HDDs, SSDs etc? I ask as my current machine still has it's stock 250GB drive. I had intended on replacing the stock drive with a much higher capacity drive except at a sane price. Having the replaced the drive with a Western Digital 500GB SATA II drive and the machine would stick, have spinning beach balls etc. This was ultimately down to how the supplied firmware (1.7) handled SATA II drives, or not as the case may be. Regressing the firmware to 1.6 allowed a replacement after market drive to work properly but at SATA I speeds. So I've wound up putting the stock drive back, restoring firmware 1.7 and decanting data on and off of the machine for the past 2 1/2 years. I'm anxious to avoid anything like this problem with a potential new purchase. I'd be looking for a 500 or 750GB stock drive from the outset so the HDD isn't so much of a problem. However the stock 4GB (2x2GB) I'd be replacing with 8GB (2x4GB) for more virtual machine breathing room. I'd be interested in hearing if anyone has had any issues with the 15" late 2011 MBPs, either with RAM replacement or with day to day usage. Thanks!