I believed I maxed out the available upgradability of my 530s.
1. CPU: Intel Core 2 Duo E8600 3.33Ghz $24
2. Memory: 8GB (DDR2 PC2-5300) $30
3. Hard drive: C: 530GB SSD, D: 4TB Hybrid $250
4. 3D Video: MSI GTX 1050 TI 4GT 4GB GDDR5 $200
5. PCI: 4 Port PCI SuperSpeed USB 3.0 $30
6. PSU: 300w Second* external PSU (Slimline Power Supply Upgrade for SFF ) $22
*Yes, I wired a external PSU to add to the primary internal power supply. There were no available high power PSU that will fit the slimline case. There are claims that they are 300w but I highly doubt it. I bought one of this and mounted it externally. It supplied the CPU 12v P4 header to the motherboard, the 2 hard drives, and the DVD burner. The internal PSU basically supplied the video card and the motherboard.
The 2 most expensive upgrades are the video card and the SSD drives, which Im still going to have to spend upgrading for a refurb or mid-level $400 dell.
The upgrade, in my opinion, was worth it since I get to keep everything I had (OS Windows 7 Ultimate and apps) and didnt have to deal with transferring and setting it up. I also slowly did the upgrade in a span of 2 months.
This is my second /backup workstation. I can now play all my Blizz games and 4K video editing with PowerDirector 16.