Did the mod today. Easy as everyone said, but the implementation isn't exactly perfect. When tripping the inertia switch there is now no ground to the fuel gage, so it pegs vertically. Theoretically you should never see this happen, and if it does you probably have bigger problems. Seems that the original wiring schematic had grounds independently for the fuel sender and pump (makes sense as there was no single unit controlling them before) and the upgraded logic unit must have mistakenly used a shared ground internally for them both. So now when you interrupt the only remaining ground via the inertia switch, the sender circuit goes offline too.