Here is some more info as most was covered previously:
At that mileage there are no guarantees, I'd want a pretty detailed service history before considering a purchase unless it was nearly free. It could run well for awhile or major assemblies could crater in the first 3-6 months and as long as you are prepared for either scenario you're good to go.
Odds are if you call most parts suppliers for Genesis parts you will be met with a head scratch as they're pretty rare. There were less than 30,000 sold in the US in 2012, a drop in the bucket compared to the 700,000 Ford F150's sold in the same year.
I'm not sure if there is a supplier for rebuilt Genesis parts so all I have to compare it to is a discount new parts supplier; here is an example of some costs for some 2012 3.8 major assemblies:
Transmission: Sale Price:$5,306.13
Engine, long block: Sale Price:$7,026.91
Engine, short block: Sale Price:$2,964.09
Here is the complete list:
2012 Genesis Parts | Hyundai Genesis Replacement Parts | hyundaiparts
Finding a competent dealer or service tech to work on these things is another challenge in itself.
Bottom line as far as I can see it; if you are looking for a luxury car that is maintenance free or you don't have the budget and/or mechanical skills to keep this car up, you may be barking up the wrong tree and should reconsider.