imac 2007/6 6,1 replace hard disc to 1 TB, etc. easier than I thought!!!
hard drive was too small at 320 GB and optical drive worked for cd's but had to slow down to 2x for dvd's and was failing.
Went well, also replaced internal cr2012 battery while I was at it!
If you have it open might as well do this with any older model. So have one ready to use. New HD was $100 and optical drive was $44.
Definitely need the torque 8 and 6 screwdrivers!
definitely need small, thin 3 " long needle nose to place screws back in place for display mounting and remounting since my torque wrench was not the magnetized type. Should be prepared to also change out the internal battery CR2012 3Volt since you have it all opened up anyway and they start to fail 5 years+. I put in a 1TB drive that went real easy. The optic drive took a bit of on job rework on the old bracket to avoid hangups. I just cut off a 3 inch strip of the upper part to avoid clearance problems when ejecting media. this left in place all pins and brackets for firm mounting. worked well after I did this. Everything now works well and my Time machine backup installed well once i got thru the unknown issue that i had to install a matching current version of the OS x on the new hard drive, so i started with the last bootable OS x which was a few back and just kept updating, up to my cloud purchased lion. note this model was manufactured in 12-06 even though i bought it in 5-07 so i will never run mountain lion the latest. So have extended it's life for a few more years I hope! I am running regular Lion without any problems with these upgrades. One other last hint, when you backup from Time machine and then start using applications I had to re-input office's code key, and several other original codes for some programs as if it was their first use, so hope you kept these from your original installs! Good luck actually went much easier than I was expecting. Opening the case was actually very easy and removing the display was very easy, but I see why Apple doesn't recommend for just any novice to do this!