Will I lose power is the header pipes get smashed or dented?
If the head pipe is smashed, dented, flattened by 1/4" to 3/8", there is typically no power loss. We have seen 7 HP loss from being dented more than 1/2" and as much as 20 HP (or more) if it is REALLY SMASHED.
We sell replacement primary head pipes for most of our systems if you accidentally smash them too much. Contact email@example.com for price and availability as not all replacement parts are displayed in our store.