Crucial for RAM is were I get my memory sticks form...The little app on their site will identify the exact kit for your Mac....I have a late 2011 MBP 17" and took it up to 16GB, quite a hit in performance...I can't recommend and SSD though, as I use a Thunderbolt storage arrangement.
I have crucial memory and a crucial M4 SSD in the same model MBP as you. Can recommend both at a big upgrade to the stock machine but have nothing to compare to on the higher end of the spectrum when it comes to SSDs etc. Good luck!
System scanner is the way to go...Apple say that my 17" MBP maxes out at 8GB. It doesn't...It happily uses 16GB and the scanner will ID the max RAm and best kit for you. It examines how much RAM is in the two slots, and gives you kit options...Best way is to use it to ensure you get the right chips.