One-use item, although buying new engine after swap grants you the swapped (not the original) engine. If you want a 2JZ in your Yaris and GR86, you need 2 engines.
Ok wait up, so I can buy duplicates of the swapped engine and use it on other cars then?
Example: I have a Integra with the K20c, I can buy two other K20c engines and dump then on my Mini and EK Civic?
More over, what if instead of doing that I can just buy the engines on the original cars and then do the swaps to the other cars? Altough I suppose the latter shouldn't be possible as it invalidates needing the roulette wheel to get the swaps at all.
Also a reminder: the text at the tuning shop says that the "new engine" option buy a FACTORY STOCK engine that was provided with the car, which is why I ask these question, because said text leads me to believe that the new engine just puts a new engine of the factory configuration in the car...
As is, I buy a new engine for my RX-7, and the game removes my 4rotor engine from it and puts on the stock REW engine from factory