as a proud new owner of an 06 un modified XK with the 4.7 and a QTII and a plan on a 2" lift and larger tires and some moderate off road travel how much of a concern are these CV joints? is this an item i should keep in my parts pile or wait until the start to go. the truck has 81000 mile on it now. it will see off road no more than 3 or 4 times a year.