Some of you are using a posi trac rear end and others are not? For those of you who have one, would you do it again or would you change anything? I hear that there is a clunk that goes along with a posi trac rear end? Have any of you experienced both with and without? I have a 600 Hp engine, is hp alone enough of a reason to get posi trac or is it just necessary for a specific application? I am still trying to get all my ducks in a row before ordering. Thanks.