Text copied and pasted from the linked Steam update (there's also a video showcasing things):

Brand New Gameplay Presets

You wanted a challenge, more variety, and more control over... everything! So we've given it to you. Starting today you can modify your trips in the Zone with 7 new presets:

Pacific Drive

The standard Pacific Drive experience - a Pacific Drive through the Olympic Peninsula.
Scenic Tour

Crafting requirements, resource consumption, driving difficulty, hazards, dangers, storms, and damage are all lowered or disabled. The player cannot die. A scenic route through the story of Pacific Drive.
Joyride

The same gameplay and tension as Pacific Drive, but gathering, crafting, and research requirements are all lowered. Damage and failure penalties are minimal.
A Sunday Drive

Focus on the Olympic Peninsula with minimal interruptions
Nuclear Journey

Every map will be filled with low dose radiation that is harmful to the player. Storms are faster and stronger, hazards and damage are more plentiful. An unpredictable, irradiated journey that only the car can protect you from.
Mechanic's Road Trip

Terrain and the status of the car impact driving more. Items to repair the car are more costly to craft, and can't be crafted on a run. A challenging drive and susceptible car will provide a test of your forethought, problem solving, and automobile experience.
Olympic Gauntlet

All aspects of the game are much harder - An extreme gauntlet to challenge the most dedicated Breachers.
Iron Wagon

All aspects of the game are much harder, and failing a run will delete your save file. An extreme gauntlet to challenge the most dedicated Breachers, with no room for failure.

It doesn't end there though, you can create your own presets with over 50 new settings in addition to the base game's existing options. Tune and tweak your trips to be as punishing or as pain-free as you'd like, all from the same menu.

New Paintable Parts and Collectible Cosmetics

Unleash your inner artist and further customize your heroic wagon! Bumpers and wheels are now fully paintable. It's fully possible for you to create the best and brightest clown car station wagon imaginable, or black out your rig for a more Mad Max style adventure.

Along with the new paintable surfaces, we've add two new collectible cosmetics to find out on a trip - an antenna topper and mirror hanger that fit in pretty well with the surreal, fantastical elements of the Zone.

Play Custom Music from Local Storage (PC ONLY)

Now that you've got a custom car... how about some custom tunes? One of the most requested features from the community was the ability to use your own playlists and music in game - and we're happy to say that this feature is also included in todays update. For PC players, you can now load your local music into a folder via local storage and Pacific Drive will pull it into the game. You'll be able to kick back and listen to it in the garage via the Jukebox or out on the road through your old station wagon speakers.

Songs are loaded from `%localappdata%/PenDriverPro/Custom/Radio/` folder, and this feature supports .wav, .mp3, and .ogg files, as well as simple .m3u/.m3u8 files.
Playlist files may point to an external internet radio stream as well (if the stream type is supported).
Enabled in the Audio settings category, can choose to have no custom music (Default), a mixed playlist of default music and your custom set, or exclusively your own music.
Reminder:
If you are streaming the game or otherwise creating content, you could be at risk of DMCA strikes or content restrictions on platforms like Twitch and YouTube if you are playing copywritten music through Pacific Drive’s in game radio. Use this feature responsibly, and at your own risk.

The Anomalous Cosmetic Pack

Last but certainly not least... we have a new cosmetic DLC pack available! This Anomalous set features parts and decals that pay tribute to your favorite weirdness from out in the Zone.

Included in this cosmetic DLC:

Mailbox Bunny (Bobblehead)
Sawblade (Hood Ornament)
Tourist (Shifter)
Anchor (Steering Wheel)
Vacation (Sticker Pack)
Anomaly (Decal Kit)

Our paid cosmetic DLC packs allow Ironwood to continue to support the game with content updates just like this one! Stay tuned towards the end of the year for upcoming details about our Winter update and more - Pacific Drive just keeps getting bigger and better and we're very thankful that you're all along for the ride.