Stage 1 is a chip only, no need to change any components at all, except I personally would be worried about HG but only one way to find out I guess, essentially the chip runs a higher boost pressure with remapped ignition and timing curves to suit. The standard MAP sensor can not see any higher boost than + 14.7 PSI (1 BAR) so would be dangerous to run more, thus it would not be mapped for it anyway.

Martin