Special Vehicles in GTA IV
Unique vehicles is not something new to GTA IV. Unique vehicles can sometimes get very hard to get as they are either mission related or they just appear as a one-time-only. Warning: do not repair unique colored vehicles, it will be resprayed with normal colors and you will never be able to revert back to the unique color. Many of Stevie's (if not all) car theft's are also very unique.
The Roman's Taxi is an Esperanto. This may be the first special car you can get. The car is easy to get, but after the depot is burned down, the cars is no longer available as it gets replaced by a fleet of grey Cavalcade.
The Laundromat is a laundry van that only appears in two mission. The most easiest way to obtain it will mission Hung Out to Dry. It can be found in the back of the laundromat, stealing it, however, will result in mission failure. It's second appearance is in the mission Meltdown where it is used in a scripted sequence. This one can also be stolen, and if you are good at driving a van in a chase, you can complete the mission without failing it.
A Sky blue Marbelle appears in the first cutscene during the mission Clean Getaway. Later in the story, when Vladimir tries to escape from Niko he drives the sky blue Marbelle again in the mission Uncle Vlad. When he reach the Humbolt River, he leaves the car and make a run for it. This is chance to take it and store it if you want to.
A pure white Blista Compact can be stolen in the mission Clean Getaway. Also this is the modified variant of the Blista Compact. To keep the car, drive it to your safehouse parking space and then commit suicide, which will result in mission failure, but the car will get stored.
Ivan Bytchkov owns a brownish and golden Ruiner which can stolen during the mission Ivan The Not So Terrible. When Ivan crashes his car into the truck, he will make a run for it, don't go after him yet. First, take the car to the end of the block to the south and park it where your will eventually get Ivan
A black-green Stallion with luster effect appears in the mission Escuela of the Streets where you have to follow it to the warehouse in Bohan. After the second cutscene, you can take it to your nearby safehouse and store it.
Gracie Ancelotti owns a special pink Feltzer that can be acquired after the mission I'll Take Her.... However, you must be a little quick to get it, otherwise, the driver will drive off and disappear.
A lustered black Coquette appears in the mission Payback. To obtain it, simply follow the goons until they stop at the building. Another Coquette with a special paintjob can also be acquired that is not mission related or anything else. Simply, if you got a Coquette, drive it to a nearby Pay'n'Spray and respray it until it comes with a white and red special paintjob.
A gold Infernus is one of the cars you have to steal for Stevie. It is a unique gold colour. Like many of Stevies cars, they re-spawn after a while.
A PCJ 600 with red and golden paintjob appears in the mission No Love Lost where you hunts down Jason Michael.The bike can be saved after the mission ends. Another PCJ 600 appears in I Need Your Clothes, Your Boots, and Your Motorcycle with similar paintjob. The PCJ 600 in these mission also comes in several variants.