from my investigation and experience, the car runs the most efficient at around 3000 to 3500 RPM.
5th gear of 3500 RPM is around 130 km/h
from KL to Penang... estimate... one full tank of petrol. that's on a stock ECU... all these settings can be fine tuned with a power FC that you can tune it to be more lean on cruise. then the story will change....
for a single turbo.... dev says KL to Penang with slightly more than half a tank.
cost of turning single....
considering all new parts and estimated only dun quote me and dun ask me where i get it.
1) turbo ~ 4000
2) wastegate ~2000
3) pipings ~ 1000
4) intercooler ~ 3000
5) radiator ~ 1000