when you say your thinking of putting it in do you mean "your" putting it in or your going to pay somebody to put it in?

if your paying somebody expect anything up to $10000 as a very rough cost.

if your doing it yourself it depends on how well you canspot a bargain. a properly completed ca18det should cost about $13000 but you could do it the cheap way and only spend $2000 (this would not be engineered and only have the bare minimum in standards