For unlock this achievement, you have to get a Perfect rating in every event in World Tour mode!
There are 169 events in total!
A Perfect Rating means you have to get the "Awesome" rating during the race and get Gold in order to upgrade your Awesome rating to Perfect (5 stars)!
If you get a Silver medal, your rating will not be improved, neither downgraded.
If you get a Bronze medal, your rating will be downgraded.
If you come 4°, 5° or 6° you don't get any rating.
There are a total of 845 stars to get.
In World Tour mode, each "rank" has a certain number of events, which will unlock as your progress through it!
Harmless: 12 Events
Unsafe: 14 Events
Reckless: 14 Events
Offensive: 15 Events
Fearless: 16 Events
Dangerous: 16 Events
Insane: 18 Events
Maniac: 18 Events
Assassin: 23 Events
Dominator: 23 Events
You can check the total of stars by going into an event and looking under its picture, if you got Perfect in every event in a certain rank, you should see wrote "Perfect" below the picture of the rank!
Here's some tips that will come in handy for getting Perfect!
Race: When racing, do no try to going immediatly for the lead, but start to takedown your opponent to build up your rank a lot faster, you should get Awesome by the end of the first lap, after that, try to keep the 1st place. Eventually your opponents will try to overtake you, takedown them. Use TURBO A LOT! Long turbo chain will help you to improve your rating (or to keep it high). Hitting traffic, going oncoming lane and taking shortcuts is a nice way to build up your rank, but avoid to crash at all cost! Use Aftertouch or Crashbreaker in case you crash, so you can inflict some Takedown!
Burning Lap/Preview: Burning Laps/Previews are all up to your driving skills. Try to learn where are shortcuts (they are usually displayed by blue lights). In Burning Laps events, try to stay most of the time on oncoming lane, it helps you to get turbo and rating faster. If you crash, most of the time, you have to restart the event. You can try to use Aftertouch and move your car for some seconds just to save second. There are some events that you CAN'T crash, especially the ones where you are using the Logitech F1 car. Drifting is also useful to take those hard hairpins in White Mountains or in some narrow road of Eternal City.
Traffic Attack: In Traffic Attack, you can win an event even without using turbo, but if you see a spot where there are no cars, boost and try to reach the nearest traffic spot to start build up your rating. Getting Skill Shots helps a lot, to get a Skill Shot you have to crash a traffic car onto an oncoming bus/truck. Not only helps for your rating, but helps even for get time and money. Try to avoid shortcuts, you can find parking cars, but they do not respawn if you get there a 2nd time, so if you run out of time you are screwed. Stay on the main road to survive. Do not use light cars like F1, use car with Medium weight!
Eliminator: Eliminator mode is basically "Last Man Standing". You get a countdown, at the end of that countdown the last car in the pack is wrecked (eliminated). Your goal is to keep 1st place for the entire duration of the event. Getting Takedown is one of the most convenient way to build up rating here, also surviving during the countdown will provide you to get some score for your rating. Crashing is deadly here, especially when the timer has almost got to zero! Try to be aggressive, but do not overdo!
Grand Prix: Grand Prix are like a champioship with 3 - 4 races. You rating carries on the next race, just be sure that in the last race you end with "Awesome", is not necessary to get Awesome in the first races, but ensure you get Awesome at your last race! Grand Prix works like races, so just Takedown opponents and drive like a maniac!
Crash: Crash may be troublesome for most people. You have to wreck chaos and create a massive traffic disaster. There are some events where you must use a certain car, but when the game let you choose, pick up either the Mobile Diner (it's unlocked when you win a medal in "Street Car Set On Fire" at Central Route - Rank 3) or the Off Road C180 Super! The Mobile Diner has a Crashbreaker power of 10, but it's slow, the Off Road C180 Super has a Crashbreaker power of 9, but it's faster and helps for all those crash events that starts with jumps/ramps in any forms. Try to block both lanes for cause massive damage, use aftertouch and get a close as possible to vehicle. There is a trick if you want to use the Crashbreaker more easily, hold down the A button to activate Aftertouch while the power meter fills, when it's full, you actually see that by pressing the B button you will detonate the car in less time, it's useful especially with the Mobile Diner since you have to mash the B button harder to charge the Crashbreaker. Exploding vehicles will multiply your score. Some events are more "Trial and Error", so take your time if a route doesn't work, try a different way to approach traffic. It's impossible you can't get a Perfect rating if you get atleast a Silver/Goal medal.
Road Rage: Road Rage are you againts a pack of drivers, your goal is inflict more takedown that you could! The opponents will try to take you down, so watch out. If you crash too much, you will get a message saying "Critical Damage", if you crash again, the events is over. Even if you do not crash, if you get slammed or skid too much a wall, your car will start to damage slightly and you will get that message sooner or later. Getting Perfect is very easy, just takedown your opponents, as they keep spawning in front of you during the race.
On latter events, you have to inflict 30 takedowns, my suggestion is to use the Etnies Racer (the Nascar car), it's unlocked by completing the Motort City challenges. Just race and slam your opponent without overdo or you'll risk to crash! Sometimes if an opponents slam you, they'll lose control and crash and you can score a takedown. It's all about skill and... LUCK. Do not get frustrated if you lose this events, the key is to drive aggressive... but never OVERDO!