2018 15" Dell XPS 15 9575 [8th,4C,G] + RTX 2070 @ 32Gbps-TB3 (Zotac AMP Box Mini) + Win10 1909 [txz81]  

System specs:

2018 Dell XPS 9575 (2-in-1) => i7 8705G, 16GB Ram, 500GB 970EVO, 4K Touch

34" Viotek UW 3440x1440 100hz 

eGPU hardware:

Zotac AMP Box Mini + Zotac GTX 1070 ITX  

Zotac AMP Box Mini + Asus Dual Mini RTX 2070 OC 

Benchmarks/FPS:

Vega M Internal	1070 External

2070 External

3440x1440 with GTX 1070 

3440x1440 with RTX 2070

Userbenchmark(1070): https://www.userbenchmark.com/UserRun/26947396

Userbenchmark(2070): https://www.userbenchmark.com/UserRun/27316010

All benchmarks done with undervolt of the graphics card and cpu (limit to 38W max).

Throttlestop settings: https://imgur.com/a/pE5DClR

Hardware Photos:

Installed a copper shim + thermal pads on the PCH; The PCH does not go past 60C, even under heavy loads. 

I run a sata hdd & all the peripherals/user inputs through the amp box mini usb ports.

Conclusion:

Works pretty well; more or less plug and play. The only complaint is that the iGPU needs to be disabled and enabled everytime the eGPU is connected. Otherwise, there is very noticeable micro stutter, and nvidia color settings are not loaded. A simple bat script scheduled at startup does the trick: 

devcon -disable "PCI\your igpu hardware id"
timeout /t 2
devcon -enable "PCI\your igpu hardware id" 

Note: devcon.exe must be in same folder as the script, instructions on getting it here: https://superuser.com/questions/1002950/quick-method-to-install-devcon-exe

Update: 

Swapped out the 1070 for a 2070. The zotac amp box mini with a 230W adapter runs the card fine. I set an undervolt profile and the power limit to 95% in afterburner just to be safe.