One PCIe X16 Gen5 slot  . . . what PSU did you get?

750 I believe

Unknown at this time. Likely will run into thermal issues if the rumors about the 4000 series power consumption are true.

I would wait for independent reviews first before worrying about upgrading your recently purchased system.

Here are some of the rumors 

Thermal issues, from what? I'm using a R13 12700 kf and with a standard RTX 3080, and test a Quadro and a RTX 3090, after contact nvidia support we shouldnt be worried about technical problems for a R13,maybe only the price will do

It's well known the higher end R13's power throttle to avoid thermal issues.

Considering it sounds like the 4000 series will use more power than the 3000 series, and the limited space between the PSU and the video card, you likely will run into thermal issues due to insufficient airflow.

I could be wrong, but from all the posts about the R13 that made it's way to this board, it does not sound like the thermals are greatly improved when compared to the previous generation.

mjah...rumors^^ contact nvidia support for direct answers.

what direct answers did you get when you contacted nVidia support about 4xxx series graphics cards?

...if you where not lazy you should know allready, basic i could put a 4090 in a alienware R13 without any trouble, or power issues.

nVidia support told you that?

what PSU did you tell them you have?

Bold statement. I would wait until release and reviews. With a 750 Watt PSU you might run into power issues for the 4090 sku.

just the one i have in my R13

Your talking about rumors while you can contact direct nvidia...

I extremely doubt you will be able to get a 4080 to work in the R13:
1) There is currently only a few mm of space between the PS and the current 3000 series cards. Highly doubtful the 4080 will be slimmer.
2) There are only 2 gpu power cables in the PS. All aftermarket cards require 3 cables.
3) The 750 watt PS is way too small, and the motherboard is power restricted.

Dell will not sell you their own 4000 cards that may be thinner with 2 power sockets. Dell will also not sell you a 1000 watt PS standalone.

The R13 is a dead-end platform, even the RAM is not upgradable due to loss of XMP. The value was there when I bought last year at launch, today I would not touch it which is a shame.

I have a few things planned to test when the 13900K and the 4000 series GPU are launched.  I won't 100% rule out if the CPU and/or GPU will be able to run in the R13, but I am skeptical for right now.  

Some of it will also depend on Dell updating the BIOS, if need be, to support the next gen CPU's.

Being there seems to be more questions about the 4000 series in the R13 right now, I might just get a 3080ti instead. I'm a little skeptical of doing the upgrade myself though. If I brought the computer to Geek Squad, would they do the install?