Tell him to avoid this tuning box! You can buy the parts from maplins for around £1.50. If he wants a tuning box he needs to look at the tunint box which is digital and works well but no where near as good as a remap.
Have a read here:
http://uk-mkivs.net/forums/p/176081/1153265.aspx#1153265The half decent tuning boxes cost more than a good remap.
Nick