I don't think i would change anything its a very solid build in my opinion. But if i had to choose it would be the ssd to the pro version. But they are very priciy in Australia like $150 when a 250gb non pro ssd is like $180.
if you have allready build it, then there is not much to change, the only thing i do not understand, is why you choosed for 4x4 GB ram, instead of 2x8 GB?