The WRC 8 pre-order page is giving a 404 at the moment but the content has been revealed by Bigben and the development studio Kylotonn.
Three editions will be available and pre-order of any edition will give you the Lancia 037 and the Porsche 911 GT3 RS RGT. For the Nintendo Switch edition, you may get a WRC 8-themed sleeve for their console (offer valid at selected retailers). Those are already some nice WRC 8 pre-order bonus.
The Digital Deluxe Edition will include the base game, early access to the game 48 hours before the official release, crew members to add to your staff in Career mode and the Legendary Cars pack. This pack includes three legendary WRC cars from the 70s, 80s, and 90s: the Alpine A110, Ford Escort RS and Lancia Delta HF Integrale.
The Physical Deluxe Edition will include the base game, a three-month subscription to the WRC+ All Live TV service (this provides over 25 hours of live coverage of each rally, expert analysis, and behind-the-scenes reporting), experienced crew members to add to your staff in Career mode and the Legendary Cars pack. Players who buy this edition will also receive an exclusive WRC-themed, collector edition, metal box.
As a reminder the game will be released the 5th of September 2019 on PlayStation 4, Xbox One, PC and in October on Nintendo Switch