Imo with all coins you earn, buy blind boxes and dismantle all the cars. Many of them were Rare and Legendary and I dismantled all of them. I had like 20,000 coins at one point and bought 40 blind boxes. Personally I got the 10,000 gears achievement before 50,000 coins (which I've yet to get). Also the amount of gears you get in career. What a grind! Probably need less than 250k coins though as many blind boxes contain Rare and Legendary cars which give you 2x and 4x as many gears respectively. So if you get the 100k coin achievement, keep going until you get 250k coins totalat any one time, then spend it all on blind boxes to dismantle every car you wantDamn lol. A blind box is 500 coins, and 500 blind boxes will cost 250 thousand coins. You'll get 50 gears per car, which would require 500 cars dismantled maximum to reach 25k gears. If we were to take the worst case scenario of having earned no gears and only getting common cars, dismantling every one you got to being duplicates, etc. 1,500 one minute races still adds up to 25 hours! The grind is worse than you think. It's a simple grind with a second console, but I'm still going to hate this game if I have to play thousands of simple races for the last few achievements. So if you get the 100k coin achievement, keep going until you get 250k coins totalat any one time, then spend it all on blind boxes to dismantle every car you want Then you have to add on even more to buy the blind boxes to get the duplicates to recycle for gears. I haven't even gotten to the 10,000 coin achievement yet - just the additional 90,000 for the final achievement is going to take 1,333 races with this method, if you assume you're swapping wins with your friend and average 67.5 gold per race. That's about the only way I could see too, but it's going to be a very long grind at that rate.