We put 16gb of memory in our PC's at work. we rarely see it using more than 8gb. I'm not sure going to 32gb is a well spent investment. As for SSD? it's the best damned thing ever. booting in under 20seconds is the best thing i've experienced in my time with my SSD. Saving your file will (of course) be faster, but the best benefit from the SSD drive is faster load times from most of your programs that cache to the hard drive or read/write to the hard drive.
I cant speak to anything about mac hardware beyond what i've said. Hope that's partially helpful.
You should buy a well used SSD (Not a knock off brand). I personally buy Samsung. I found their 840 Pro line was very good. I havent used the EVO line but most people ive heard using it are very happy with it. I have a Corsair Neutron in my home PC. It also works very well.