If it's not really about tuning or wiring. Then it belongs in here.
As above im just looking to get peoples opinion on these for the fuel and oil system?
Hard lines can have better flow, but are a lot harder to work with than flexible hoses, you can probably get by with much smaller hard lines than flexible lines. For braking systems, hard lines have an additional advantage as they do not expand with pressure, but again they are harder to work with.