$750 is list. Do we even know what all that includes yet? Many dealers give a discount if you ask for it and some even give deep discounts (like 10% above cost) for clubs and such. So it pays to shop around.
As for 7 to 5 mic, it is more than that since you will be getting a separate water separator and revised lift pump. Clearly the stock system works to a point, but due to its small size and using one element to do two jobs, it is limited in what it can do in the case of a bad batch of fuel.
Plus the kit is designed as a system, so that all the parts work together, under all conditions, which should put it a far cry above just adding filters a stock fuel system. I also like the heater, especially as the stupid politicians force more and more bio content down our throats.
As for the fuel tank vents, it will be interesting to see what gadget they come out with. I simply capped the tank ports and use a vented fuel cap.