Yakuza Kiwami

Pocket Circuit is available starting in chapter 4 but I would wait to complete this until after you get the parts from Purgatory's weapons dealer in chapter 6. He will have a couple parts necessary for the builds I am going to show you.
Credit for these builds goes to kouryakutsushin.com.



Above is a chart I imported to Excel to make it easier to read. Everything worked including the boost at the champions cup. You do not need to do the side-story quests related to Pocket Circuit just the tournaments for this to count. For the parts remember that after every 3 races you win the parts shop will be updated. Remember to bring a fair amount of cash for the last few upgrades they cost a pretty penny at the end. Also don't forget to check Ebitsu Pawn for a couple of parts but you can get those starting in chapter 4. Reminder, a couple of parts are found in Purgatory so again stop racing when you get to the Intermediate cup because the super slick tires are found at the weapons shop guy in Purgatory in chapter 6. The bumper plate can be swapped to the new bumper plate but I saw no difference. If you are having trouble at any of the races it is either because you are still flying off the track, which is just rng, or you are not fast enough/too heavy, I recommend switching cars. I used the Killer Bee found at Ebitsu Pawn for most of my races and the Devil Killer for the final race. You may not be able to use Killer Bee from the start because of the parts restriction but the starter car works just fine. Good Luck!