is my rig going to cut it?

[artantaaa]

You're right that ram is more expensive than most, and you don't need 8GB for dolphin either. You could also get good performance from an i3 since dolphin only uses 2 cores. Here's one for $125
http://www.newegg.com/Product/Product.aspx?Item=N82E16819116946
Good luck with your build.