Talk:Mazda 6/@comment-31458611-20170626163136/@comment-27736210-20170705034156

By the way, the super simple way I found out this trick was...

Tuning Kits give the car the equivalent performance of all MAX upgrades +1 level.

So a car with tune 2134 0314 would end up having the equivalent tune to 3245 0314 with a Tuning Kit. The fifth level gives an imaginary value which is calculated by dividing the total speed increase (from default to max) by a certain number (maybe 33 percent?). The fifth level always ends up being a tiny bit lower than the fourth level, in regards to the Tuning Kit boost.

This simple rule means you can predict Tuning Kit bonuses by looking at the next MAX level, however, it's a bit harder to predict the Level 5 bonus, but you can base it on the previous value, minus around 5%-10%, to get a rough idea.

Also, this means that the Tuning Kit bonus number (eg 90 for the SUBARU IMPREZA WRX STI) is directly related to the rank difference between default and MAX. The Renault DeZir has the largest Tuning Kit bonus in the game because it goes from around rank 500 to around rank 1100. The other cars that start at rank ~500, such as the SUBARU and Camaro Z/28, all have gigantic PRO upgrades. Instead of adding 109 ranks, like the Renault DeZir, the SUBARU and Camaro Z/28 add something between 250 and 300 ranks. This is bad because the distance between MAX + PRO becomes smaller; you have to subtract around 260-280 from the total of 1300-1350, leaving around 1050. The starting rank of the Camaro Z/28 is also around 50 higher than the Renault DeZir. This results in the Camaro Z/28 receiving +87 for its Tuning Kit, and the SUBARU receiving +90 for its Tuning Kit, instead of the perceived +128 that the Renault DeZir possesses.