New back box advice please
 

Hello all

I have just purchased a Dansk twin outlet sports exhaust back box for my 89 3.2 to replace my blowing OE box, I'm thinking of fitting it this weekend and and would welcome any advice if you have already done this to yours? The thing that concerns me the most is cutting the rear valance for the extra pipe are there any tricks to doing this?? and any other advice to help me on my way would be much appreciated.

Paul