Got the case. S4M.
The question is what are the best gaming components I can cram in. Without modding the case. Prefering PSU inside. Having a brick outside is an option. Money is no object for this client.
Go!
Many thanks in advance for help.
Graphics,
If you're willing to go with an external brick, than a Zotac 1080 Ti mini, or a Zotac 2070 Super mini will fit in fine. Both can fit in brickless with mods however.
If you want a brickless build with few mods then a 2070 or 2060 Super is perhaps your best choice.
CPU,
Look up benchmarks for what the Noctua L9i can handle. Myself and a few others have thrown delidded i7 7700K's and 8700K's in there without having to underclock/undervolt it. The i7 9700K shouldn't be an issue. I've seen a few people throw in a Ryzen 3 3700X, but you'll need to tweak that one.
I'd be weary about stepping up to an i9 with the L9i... esepcially if it's one you can't underclock.
CPU Cooler,
Options are basically L9i, or the LP53 with a noctua fan. The alpenfohn black ridge will fit but you'll have to bend it's heatpipes, check out Josh's youtube for that.
Ram,
Basically limited by height. Corsair Dominator and Vengeance Pro RGB ram won't fit. If you're after 64GB ram (2x32GB) the only decent option (IMO) is Corsair Vengeance LPX.... if you're ok with 32GB (2x16GB) then there's plenty of choices. G.Skill Trident Z is a popular one. Well priced, good timings. Quality chips. etc.
Storage,
Depends on your motherboard. If your motherboard has a front m.2 slot, then the new pcie4 m.2 ssds (for x570 boards) with the giant heatsinks will be fine. On a rear-slot m.2, anything with a large heatsink will be too tall.
You've also got the option of 2x2.5" drives.... For maximum storage, Seagate's 15mm high 5TB drives will fit, but if your graphics card doesn't have a backplate, it's recommended you get come kapton tape or something between the hard drives and back of the card.