The "sport tuned suspension" was a 1mm larger frt and rr sway bar and different coils. Still way too soft IMO. I'm on H&R springs and a 03 Tib 19mm rear sway bar. Car is night and day different. You get bored one of these Sundays and I'll toss you the keys.
As for my mileage, the Elantra is picky. Anything over 3200rpms and the ECU goes into WOT tuning mode. So with a 5 spd, that means you want to keep it at or below 74mph. To go faster, I've gone oversized on my tires (sonata 16" wheels and 205/55) so 3200rpms puts me closer to 80. So when I want to run 75, it thinks I'm running 70 and the engine spin slower.
Next, open up the intake. This car is really choked from the factory. The first step would be remove the resonator from the fenderwell. If you really wanted more, step up to a true CAI. Over inflate to 37/35 f/r tire pressures and you're golden.
Also, don't trust the trip computer for mileage. IT's about half right half the time.
There's a couple of good online resources for this car, www.elantraclub.com being the better of the two for the "more mature" generation such as myself!
EDIT: Ted, on vacations, we get 36-38mpg with the car now. Just for reference.