u/Sufficient_Sport9687

I am a US Citizen and have a 10 hour layover in Incheon airport. I am traveling Korean Air business class. My goal is to head into Seoul for a few hours of shopping. I get in early in the morning around 6am. Plan is to deplane, head to the lounge, take a shower, eat breakfast/coffee before heading out. I have a few questions:
1/ Is the East lounge the new renovated one and best for using showers?
2/ Can I leave my carry-on at the front desk so I dont have to lug it around?
3/ I am assuming after freshening up, I will need to go through immigration. Do I just fill out the e-Travel card or do I need to do K-ETA?
4/ I will be looking for men's streetwear so will head to Seongsu area. The stores I am looking at are Musinsa, Coor, Pottery, etc.
5/ Let's assume I buy 6-7 things, I just realized how will I bring them back through airport security? They might not allow me to bring those items unless I consolidate them into a carry-on bag or something. Is that assumption correct? If thats true then I will look to store the carry-on bag somewhere in the airport before the security check in. What would be the best place?
6/ I am assuming Uber from Seongsu on Monday around 1pm would work?

I bought a base 2026 911 Cabriolet recently and I have been enjoying it a lot. Right now the base is my daily car. I was thinking of upgrading to a 2026 Carrera 4 GTS Cabriolet from the same dealer. Does it make sense to upgrade and is it good as a daily driver?

My car after taxes and upgrades was about $165K (~180K after tax). I see the GTS' that the dealer has are typically in the $226K range. What can I expect in terms of trade-in value? I have driven it for 4-5 months and it has about 3K miles on it.