The only modifications are rally wheels and moving the gearshift lever from the column to the floor. This car is equipped with a factory overdrive transmission therefore it can cruise at existing highway speeds This car also has dual exhausts as well as an oil filter up grade (spin off/on). This is one cool 4-dr sedan that is absolutely cherry. Engine has been rebuilt 1300 miles ago. Vehicle painted 3 years ago. This car has always been garaged or under cover, never sitting outside. The appearance of smoke coming from the exhaust is merely condensation as the car was cold when we took the photos.