GTR2 lacks some of the conveniences which the current generation of sims offer. One feature it lacks is the ability to automatically adjust your wheel's steering lock.
To make manual adjustment a little easier, for the Ford GTs, the Porsche 906 and the Alpine A110, the specs have been amended to indicate the steering wheel lock in turns and degrees.
So if you want to set your wheel to the correct lock you can select your car, go to the showroom, click on the History and Specs box and find the correct steering lock for that car. You can then alt-tab out of GTR2 and set your wheel lock using your wheel set-up software, and then return to GTR2.
To get the appropriate steering ratio, you will have to adjust your steering lock from 900 degrees for the new Ford GT MkII and the new Porsche 906.