I had a single AN8 braided rubber line through the car previously and used the factory hardline for the return.
Fuel will permeate rubber lines so although not leaking the fuel smell will seep through them. I could have used teflon lines instead but using the OEM hardlines is a better solution for me. All joins will be outside the cabin except the ones in the boot but the boot is going to be firewalled and sealed anyway.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds