30mpg is about normal for a well maintained 1.6L 16V that has stock tires.
I am running 31" MTR's and get from 20 up to 30mpg depending on if I drive like grandma or like my son, LOL
a stockie can run 70mph all day long and then some.
All 16V 1.6L engines have a multi port injection. MS can be used without many issues at all.(though MS will not pass a OBD inspection)
They all have a mechanical clutch fan, no need for a electric fan.
A GM12Si alternator can be installed very easily, a TT install bracket will be needed, it is cheap at 25$
Tons of rear leg room on the 4dr
You can convert the wheel hubs to manual very easily, though you will not see any mileage difference at all.