Hello, I am looking at 13" MacBook Pros and is am wondering how much of difference there is between the different i5 speeds. And, how much of a difference I would notice between 8GB and 16GB of RAM. I will be doing web design and development (Photoshop/Illustrator/Dreamweaver) and multitrack, live vocal recordings with Garageband. I just want to know if price increase for each model is worth it, will 8GB be enough for what I do and do I really need to look at a quad-core processor. I mean, should i notice a difference between speed and performance between the 3 models available? Thank you in advance for all help.