Do you reckon I'd loose power with putting a backbox onto the car? 2.0 tfsi, there will also be a 3" decat downpipe on to standard centre section

i wouldn't have thought you would loose power but I'm not a computer wiz who knows about remapping. on older cars a decat and a different back box would help improve BHP as it is just allowing the exhaust gasses to get out quicker. as its newer it might rely on the back pressure sensor. but if you have had a decat and that has been removed from the brain it shouldn't really bother it. at the worst it won't change the performance but enhance the sound.

a second hand cat-back would prob not cost you much more? If you retain the stock restrictive centre section then there's not much point in the back box?

I doubt a back box alone would gain you Amy noticeable performance, but it would only be detrimental if it were more restrictive I think.

I have a 3" rolled out backbox , that I vantage remember the brand of, that would look cool on the Octavia so cost isn't the thing, just fancied something different, and maybe get the milltek non res centre section with my 3" dowbpipe and connect it all