I have a 2006 REV 800--144". I am adding a longer track this year and will have to do a tunnel extension. Question 1: When you add a tunnel extension, Do you have to remove the stock tunnel piece then replace it with the new extension or do you put the new tunnel extension on top of the stock one? Next question: When you do the tunnel extension, do you have to move the cooler back or just leave it in place?