Does a big bore exhaust take away power?
Depends on the people putting the exhaust together, if it’s a simple huge rear box attached to a good system, then it will be fine. If someone has put a big bore all the way through, the likely hood is that there will be not enough back pressure, so at low revs it will be down on power, but at the top end it might be slightly better (might). Big bore is not usually a good way to go as most road engines aren’t designed to run with little back pressure, so performance will drop as will fuel economy, all you will get is lots of noise and less oomph.
