The first car I ever owned was this 1953 Chevrolet 2-dr sedan.  I paid $100 for it at a used car lot.  It had been mildly customized with a tubular grille but retained its original 6-cylinder engine.  I added the baby moons and whitewalls to the tires.  I drove it my senior year in high school and to my first job at the GM Technical Center.
The model was built to represent a drag race version of the car...a 'gasser'.  Cars fitted with drag slick rear tires, lifted front ends to aid weight transfer and hopped up engines were all the rage in the 1960s.  This is what my high-school car might have looked like had I had the money to build it!
While on a trip to Havana, Cuba in March of 2019, I came across a car much like the one I owned and modeled.  Except for the portholes on the front fender and the trick aluminum wheels, this was a nicely restored car.  I don't know what engine was in it, but most of the 7000 period American cars in Havana have had engine swaps.
The first new car I owned was a Springmist Green 1968 Pontiac Firebird.  It was equipped with the 350 cubic inch V-8 and 4-spd manual transmission.  The car had a black interior.  I drove it for over 75,000 miles including two trips from Michigan to California.
The starting point for the model was a Revell '68 Firebird 400 kit.  the body was painted with Testor's Gloss Metallic Silver.  Twin velocity stacks are fitted to the 4-bbl carbs on the blower.  The wheelie bar assembly was scratchbuilt and the fuel tank was removed in order to accommodate it.  Wheels and tires were from the kit.  Seat belts and a fire suppression system were added to the interior.
Cover of 1968 Firebird dealer brochure
Concept sketch for model

I bought my first car in my senior year in high school, a 1953 Chevy.  My next car was a used 1962 Olds F-85.  The first new car I owned was a 1968 Pontiac Firebird.  In graduate school I bought a 1972 Vega.  Plastic 1/25 kits are available of all these cars (although a model of an F-85 is rare and therefore very $100) and I used these kits to create models recalling three of my first cars, as they 'might have been'.
A fraternity brother, Pete, (sitting on the car) bought this brand new saddle tan, 1964 Corvette convertible, 327 4-spd.  My brother (left) and me (center) were photographed with the car in the driveway of our home in Farmington, MI.  As I recall, this was the first time I saw the must have still had that wonderful 'new car smell'!
After I sold the Firebird, I ordered a silver Vega GT with the optional 'skunk stripe' as in this brochure photo.  It was the last manual transmission car I ever owned.  The Revell Jungle Jim Vega Funny Car in a silver and black scheme will provide the 'hopped up' version of my Vega.
The model was built from a Revell kit with enhancements.  The Chevy 409 engine is blown with fuel flowing through two 4-bbl carburetors.  The exhaust headers were scratchbuilt from .080 diameter plastic rod.  The seat belts and harness were made from painted masking tape and a fire extinguisher was added between the seats.  The roll bar was made from sprue material from the kit.  The shifter is a round-head pin.  The front and rear wheels and tires were purchased on eBay.  The steering wheel is from a kit of an Indy roadster.
The model was built from an AMT 1963 Corvette kit.  The exterior color is Testor's Bronze Extreme Lacquer.  The 427 engine from the kit was used with 8 Weber carburetors fitted.  An opening was cut in the stock hood for clearance and a simple scoop was scratchbuilt from styrene.  The wheels and tires are from the AMT 1963 Corvette coupe kit.  The two roll bars are made from 20 gauge aluminum wire.  The exhaust tips are 1/8" diameter aluminum tubing.
Styrene rod was used to fabricate a 'filler' between the kit's headers and the molded-in exhaust pipes on the underbody.  The convertible top was left unpainted as I felt the color was perfect with the bronze paint.  It was given a coat of Testors Flat Lacquer.