Looking for advice about upgrading hardware in a 5 year old Hackintosh.

Five years ago I built this PowerMac G5 Hackintosh/gaming PC and it's been my main computer ever since:

https://pcpartpicker.com/b/Zfxrxr

Quick parts summary:

• Gigabyte GA-Z77X-UD5H ATX LGA1155 Motherboard
• Intel Core i5-3570K 3.4GHz
• Gigabyte GeForce GTX 670 2GB
• Custom modified PowerMac G5 case

It's been an extremely stable machine and I've upgraded the OS to every major version from 10.8 to High Sierra without much issue. I've gone up to 16 gigs of ram and changed out the hard drives/SSDs since the PartPicker build listed above, but the CPU, GPU, and Motherboard are all the same from 5 years ago.

I'd like some suggestions about upgrading the hardware. I don't want to change something and suddenly find myself having to mess with drivers and kexts more than previously. This build is basically stock with regards to software. I just run the TonyMac tools on default settings and away I go. Doesn't require any GPU drivers or any custom kexts outside of basics like FakeSMC.

I think I'd particularly like to upgrade the GPU for better gaming performance in Windows, but I'd be interested in any suggestions about where to spend a few bucks on upgrading.