To complete the accolade you need to buy 400 cars from the Autoshow to get as reward the Jaguar D Type.
If you want to complete this accolade you can do:
1)You can get the same car for a low price like 20k credits
2)You can unlock mastery rewards from the cars you buy(wheelspins and more…)
3)To do this think all you need is to have at least 8 Milion credits
4)You can gift the cars or simply remove the cars from the garage
5)When you buy a car perss more times the buy button(for example press A button more times or the button you need to press to buy a car)
I hope this was helpful
Sat1212