Brocks twin system CT is full exhaust , that will be very light weight ti system , the TBR I am not up to speed about at all . The full Brocks dual CT will give you a un-restricked exhaust , that will require fuel mapping PC5 etc. to work best .
Your post mentioned the above pipe ? , but you also ask about slipons , I do not think Brocks CT dual comes in slipon kit as well . Any slipon fitted to Gen 2 will really only change the exhaust note mostly and generally does not require fuel changes to be okay , and I would expect sort of similar to stock fuel mpg .