Fitting a wier kit into a Supra diff is very simple iv fitted one in my focus Supra diff and modded a spare I have . If your not happy to fit it your self I would think the company that checked it over should be able to fit it as it does come with instructions on how to fit the kit .
i just went on the website checked out witch kit I won'ted and payed for a week or two later it was at my door