If you are having trouble with driving in traffic like I do I accidentally stumbled upon a great way to get the 100,000 points easy.
What I personally did: I got the 2002 Nissan Skyline GT-R V-SPEC II and fully upgraded it to S2. I haven't tested it but I believe any all-wheel drive Japanese vehicle will work.
Head to the first barn discovery location (if you haven't gotten that far I detail it in the beginning of the video) and go to the fields directly to the east of that. Then simply do doughnuts/drifting/E-braking in the fields while trying to move from one end of the field to the other. You will get Wreckage, Wrecking Ball, and Sideswipe bonuses along with Air, Kangaroo, Crash Landing, Drift, E-Drift and Skill Chain bonuses. I messed up a few times and have some of my stuff upgraded to make my multiplier raise faster but this is how I originally did it. You just need to get 25,000 points at 4.0 or 20,000 at 5.0.
This is also how I got a bunch of extra points and have pretty much upgraded all my skill shop points as of right now.