3 year old car in the salt belt = break out the torch to loosen things. It's not bad enough that most manufacturers are using Loctite or nylock nuts on every fastener they can, but add a few years of excessive road salt and all bets are off getting things loose easily.
Both my '88 K Blazer and my '01 Sonoma seemed to hold up pretty good for about 8 years as daily winter drivers, then within about a year body rust broke out all over. I remember reading back in the late '90s that the Big Three put thick enough galvanizing on the sheet metal to last about 7 years in a salty environment. Galvanizing is sacrificial to steel, so I think it gradually erodes away until there is nothing left but the steel, then the rust starts.
I live right on the edge of the rust belt. 50 miles north and cars dissolve. 50 miles south and they stay fairly rust free. I try to buy cars from south of I-64. A 3 year old car is probably a lease turn in. You do NOT want a turn in from up north. Someone who buys a vehicle will rinse underneath from time to time in the winter. A lease holder probably wouldn't. The body parts aren't the problem they used to be. Steel fuel and brake lines are another story. A neighbor used to live east of Gary. I helped him replace the brake lines as they rusted and blew out. Really interesting for that to happen if you're one of those big city people who wait until the very last second to brake.
I worked on a friends Windstar that came from Chicago. Her main brake line from front to rear had 3 patches in it with compression fittings. I told her it should be replaced with new line front to back. She just wanted it fixed so I added to the mess with a new section and did flared fittings. That worked for a while until another section started leaking. Windstars have the ABS unit mounted down low in the front. Every one of the fittings was rusted bad. I told her to dump the Van because it was going to be safety thing very soon. I saw it in the J/Y a couple months later with the front end smacked in. Not too bad but I knew it was coming. The top part was in great shape but the underside was beat up by the salt.