GT Sport: A Guide to Quick'ish' & Easy Credits
Using this guide will earn you 345,000 credits in about 12 minutes of racing. I'll be showing you which car I use, the setup for it, and which race.
The biggest keys to making bonus credits are clean racing and being under powered for the opponents you face. My car of choice for this method is the Porsche 911 GT3RS. I believe it to be an amazing road car in the game, it grips and corners almost as well as the racing spec cars. Set to 90% power and 87% weight reduction, it qualifies as the N400 category. This is pretty much the lowest power I could manage and still catch the N1000 opponents with relative ease. Below are screenshots of my car setup, the only things that really matter are the power, weight, gearing ratios, and super soft tires. Everything else is just personal preference.
The race I use is the one pictured in the title. GT League, Professional level, Premium Sports Lounge Race 1, at Blue Moon Bay Speedway. The base prize for 1st place is 100,000 credits. Just winning this race with a N400 car gives you a +130% car handicap bonus. Combine that with the +50% clean race bonus and you get 345,000 credits. In just 15 laps which are easy to average 48 seconds a lap, it is a very efficient way to earn credits. If you don't get bored of turning left, you can grind this race for an hour and make 2,070,000 credits. I however, do get bored of it and can only do a couple times in a row.
The only real challenge to this credit farming is the LaFerrari. When the opponents randomly generate, you won't always have to face the LaFerrari, but when you do, get ready to do some blocking. When you finally do catch the 1st place LaFerrari around lap 11 or so, getting around it in the turns can sometimes be difficult depending on traffic and it's very fast acceleration. Once you do pass it in a corner, be ready to block it down the whole straight. If you get out in front by a couple seconds you should be fine, but keep an eye on the rear view because the LaFerrari comes up like lightning in the straights.
Try it out for yourselves and enjoy! If you know of similar or better ways to get credits, please do tell me in the comments. Even with this guide, I still don't have the time in my life to grind for the 20,000,000 credit cars.