You already asked this.
The answer is still: Think about about it...you really should be able to answer this yourself.
Stock size is not 3" - meaning you will need to flare the cat's flange to that size, or change the entire exhaust to that diameter. If youre only planning on a 3" dp and 2.x" piping behind that, youre not gaining anything but monetary loss and backpressure further down the line.
3" is ridiculously large for n/a hondas