Just wanted to see what other people thought was a good size? I am going to get full mandrel bent with a hiflow cat and a straight throught glass pack muffler, was thinking about duels, but then the extra money and extra wieght

ATM it is just std with a set of extractors. I think it has been suggested that 2 1/4 is a good size? Would 2 1/2 be too large and not give enough back pressure?
Opinions?