My Z was in nearly mint condition when I bought it in early 2001. Now at 136k miles, it can still consistently run the 1320 in 14.7 sec. Major mods: K&N intake, JWT ECU, headers, exhaust, lightened flywheel, clutch, lightened crank pulley, SS brake lines/syn. fluid. I have yet to experience any ill-effects as a result of these mods or my daily heavy-footed driving. I get an avg. combined city/hwy mileage of 22+ mpg. The driver's seat lower left side bolster is worn through to sharp metal. This is a std. flaw for this car. All of my pants belts have scratch marks on them in the same place. Ordinary drivers (80% bad) will annoy you. People will want to race you. Cops will suspect you.
Improve stopping distances. Lighten the Zs weight. Improve transmission (gearbox was redesigned in 1997, one year AFTER the end of US sales). Lower maintenance cost (oil, tires, filters, transmission(s), shocks, wheel bearings, bushings, repair of body damage, brakes, clutch). Security. Cupholder.