It's Apples own proprietary connection. You will only be able to purchase OWC and Apples products right now. Also, it isn't an SSD in the MBPr, it's flash storage. They are predominately the same thing except that Apple doesn't use an enclosed case for their storage and it's proprietary connection.
It's possible. And by saying possible it is no where near easy. You have to dive into Terminal and start tweaking OS X code. Which can be very dangerous. You can search the web for DIY Fusion Drives and many of the articles explain a lengthy process to get it to work. Here is just one. http://www.zdnet.com/diy-fusion-drives-not-for-the-timid-7000007377/
Even with the thin display it is glued to the body. Which takes a heat gun and a bit of force to get that display off. With Thunderbolt and USB 3.0 as interface options I would highly recommend buying an external drive instead of trying to open your iMac. It would be a shame to pay a premium for the computer to break the (probably) expensive display.
I am guessing your MBPr came with the 128GB storage option? It says in the teardown that a 9.5mm HDD just doesn't fit and could possibly fit the 7mm or 5mm but the problem comes in with the cables and mounts. Apple uses proprietary cables that are only used in their flash based storage so even if a super slim drive could fit you would have to work around the additional cords and also how to fasten it securely in the housing. Your best bet is to just upgrade the flash storage with something like the OWC Aura. It is much easier. You are however going to have to pay a premium for that ease. The best part is that if you replace it with flash storage you will still have extremely fast startups and data rates that you just couldn't get with traditional drives. Here's the link to the OWC Aura: http://eshop.macsales.com/shop/SSD/OWC/A...
Hey Rudy, you can actually change the field of view (FOV) within the GoPro settings. You can choose from Wide, Medium and Narrow FOV's. If you press continuously onto the on/off button until you see the wrench then press on the top capture button you will enter settings. The first selection press the capture button again. This will take you into the video settings. Press on/off twice and hit the capture button which will then allow you to choose between the 3 FOV's. If you scratched the lens that is on the protective shell then GoPro sales a screen replacement for $20. The link to it is below. http://gopro.com/camera-accessories/hero3-lens-replacement-kit Now if you scratched the conical lens on the main GoPro camera, I do not believe there is a user accessible replacement for it. You would have to contact GoPro and probably have to send it in for a replacement.