I max out at 38,000.
Should I let it get close to maxing out?

The best I have got is an expansion of 60 cargo spaces for 20,000 points. (Mass Storage Pod) Is that the highest?
Is their a list of artifacts and the point cost? I saw a pretty good list on the wiki. Is it up to date?

20k it's the most expensive artifact, Mass Storage Pod. As for a complete list, you can see it on wiki.

Here:

http://galaxylegion.com/wiki/index.php?title=Artifacts

Ok didn't realize that the wiki is up to date.
Does anyone have any idea of the %chance of receiving those artifacts listed?
Does Dan release this info? Or is it complied by players?

No, he has not released this info. I can tell you from experience:

Exceedingly Rare (almost 0):
Quasi-Spacial Expander
Mass Surface Melter
Planet Flux
Terraforming Device


Common:
Android Helmsman
Processing Core Chassis
Relay Tower Chassis
Refining Lab Chassis
Android Scientist
XCharge Cells
Durtanium Brackets
Phase Cutter Chassis
Warp Gate Chassis

Uncommon (compared to the common):
Tesseract Container
Space Elevator Chassis
Spy Uplink Chassis
Time Manipulator
Alien Data Disc
Engineered Virus
Rescued Prisoners
Ship-Bot
Star Chart Purger
Alien Star Charts
Mass Storage Pod

I believe everything else I would consider exceedingly common...

ODragon

Thanks. This gives a little more of an idea.

The ones we want are not common and the ones we have to many of are common.

That's how I was computing it. That being said, there are many of the commons that you can't have enough of (Android Helmsman, Android Scientist, XCharge Cells, Durtanium Brackets). The problem is, I have more than 10 extra processing cores, relay towers, etc but I can't get enough Spy Uplink/Space Elevators. However, looking at the numbers again, they may also be common but since you can use 2x as many of them on planets, it just doesn't look that way.