I'd mod my car extensively. I like the power, light weight, handling and I've learned so much about the ecu I can tackle anything with it.
Build an Miller cycle engine by recombining current parts. Find a 1.8 liter Mitsubishi Cordia engine block, which just happens to use the same stroke as the engine in my car, but it has a 5mm narrower bore. That would reduce internal friction a little, but more importantly a long stroke motor is better suited to Atkinson/Miller cycle. Use high compression pistons, 11:1 would be good, 12:1 better,
aw what the heck, it's just a daydream, so lets shoot for 13:1 compression!
Combine that block with my excellent (cough) dohc head. Get custom cams. The intake cam would have lower lift but much longer duration, like an Atkinson/Miller cycle motor. Adjustable cam gears insure years of tuning enjoyment.
I'd keep the turbo, maybe downsize it to suit the power characteristics of the homegrown Miller cycle engine. Find what works.
The next step is swapping an AWD trans and transfer case out of a 1990-1994 Eclipse/Talon/Laser (because it bolts right up). Swap in a taller 5th gear from a EVO GVR4
www.vfaq.com/mods/Trannies.html. Instead of a driveshaft going to the rear wheels, I'd keep the back wheels unpowered, remove the driveshaft, and hook up an electric motor/generator to feed power into the tranny through the transfer case output shaft. Lock the front driveaxles to the electric motor by simply welding the center diff. This would let the electric motor propel the car with the engine off and provide a slight gear reduction so the electric motor could be downsized. The engine could be uncoupled from the electric motor simply by pushing in the clutch and/or shifting to neutral.
To uncouple the electric motor from the wheels I'd need a JDM switchable tranny or transfer case.
www.vfaq.com/mods/Tranny-switchable.html An electric solenoid could be attached to the plunger bolt actuator so the electric motor could be coupled/uncoupled from the wheels with an electric switch in the cabin, or by ecu control.
Or maybe I could just turbo an Insight.