Heh...I know the guy that used to have that Cobra vert. Your friend will do well to just shift at 2000 around town. When I drove mine daily, I'd get a mixed (some city, some highway, mostly stop and go) mileage of 17.5. That's with a mostly stock powertrain (engine, trans, gears). If I'm not mistaken, that vert wasn't modified.
'03 Cobra - Mildly modded. A work in progress. 12.566 @ 110.755, 1.89 60' on street tires
'93 Notch - Looks faster than it is.
'72 F100 4x4 - Dormant, for now.
Race '99 L - 12.40 @ 110