Here is a tutorial to find some rare cars the cars
Coquette is a car he looks like a corvette and the car is apparently really rare on the game and only spawned in a certain mission
1st Go to Rockford hills then quick save the game (at the clothes shop at Rockford hills)
2nd reply the mission called "mr Richards"
3rd get in he coquette it's right in front of where the missions starts
4th drive to the mission way point in the coquette without changing to another car
5th compete this mission
6th you will get re spawned back to where you quick saved it
7th just drive around the corner and you should see one parked there or some driving about
This photo is in rockford hills where i saved the game and where I found it after doing step 1-7
The dominator ( the ford mustang or you could say the Shelby gt500) p.s I found this tut on a gta forum
Take your character to a spot where cars are spawning and driving by constantly. ( I saved it at the hospital with the ladder to the roof)
Quick save your game from the cellphone.
Go to the pause menu and go to "GAME" and click where it says 'Replay Mission' and search for the mission "The Wrap Up"
Finish the mission, right before the end, there will be a parking lot where MerryWeather has set up shop trying to kill you and dave. You gotta clear them out and make sure all choppers and MerryWeather troops are gone.
(5). DO NOT steal any of the MerryWeather cars, You want to run to the end of that lot and you see a parked Vapid Dominator (Will be in various colors) next to a wall. Get in the car and outrun the chopper chasing you.
(6). Proceed to complete the mission and once its done after you talked to trevor the screen will go black therefor teleporting you back to the spot where I told you to go in Step 1.
(7). Look around for a Vapid Dominator because they will be spawning around the city (it will take some time to find it but i swear there will be some around. I've tested this NUMEROUS times to be certain and it works EVERY time.)
(8). Once you find your Vapid Dominator, you want to bring it to your garage, (NOT your home garage.) The garage you pay for unless you got it with a special edition or collectors edition pack. Just be sure you dont bring it to your actual garage at home because IT WILL disappear and then you have to do it all over again.
(9). Leave your garage, Save your game, Walk back into your garage, and there ya go.
(10). Once this is done Vapid Dominators will be spawning everywhere around the city, grab some, customize some, have a blast. Hope you guys have fun and I hope it works for you like it did for me.
The Adder (buggati)
Sometimes During the game You will find a Adder just sitting out side the clothe shop in Rockford hills is usually back with yellow strips or white with back stripes
for A direction to the shop drive out Michael house drive way take a left and drive straight down the hill and you will reach a clothes shop called ponsonbys ( Its not always there but usually is when you first load the game again after quitting it. I know you can buys this on the in game internet but it saves you $1.000.000)
For the Grotti its really easy to find up near Michael and Franklin house but sometimes is a pain to find so hear is a tut
1. Quick save it in the rich areas like Vine wood and Michael house or Rockford Hills
2. Reply the mission called "Legal Trouble"
3. get in the Grotti its yellow well usually is
4. basically complete the mission in the Grotti make sure when you reach molly you need to get out of the car so part it in a safe place when you get out it and after you get the tape get back in the car and lose the cops
5. it will respawn you where you quick saved it and you should see it driving about everywhere ( I don't have trouble personally finding it but some people do so here is a way to find it)
6th just drive around Rockford hills and you will see it
Here is a place you can look to find all types of cool cars and rare cars Like the 9F (audi r8) the car that looks like a Mercedes (two door one) and the super diamond (rolls Royce) and sometimes a comet ( I know half these can be bought online but still saving money
What you would do it go up the road I put in the image above and you will see a petrol station or a gas station if your american ect
What you want to do is save the game there (quick save) load the save again and new cars will be there and usually for the first few mins its really good rare ones that you don't usually see driving about the street. If there is no car there you like Just reload it again and new cars will be there I done it 3 times and the infernus and all those types of car were spawning.
P.s The photos are bad quality because I took them with my IPhone 5 and that camera Is really bad