Well, i also did some research for my khyber a year ago.
it was around 6k to 10k expense.
but i did'nt go for it, because a sincere shopkeeper told me that it will be troublesome with an old car(mine is 94 model).
if u still want to go for it, then i advise u to change all the channels and machinery.
and go for some good second hand japanese ones.