hi ther i could do with abit of help i hav an evo 4 but hav been told it may hav a evo 6 rear diff in it, how can i check if it is evo 6 diff an can u use an evo 4 transfer box as im guessin evo 4 transferbox is not lsd an the evo6 rear diff will be pluss are the ratios the same ,, despratly need help thanks..