I beg to differ, i pulled the emissions control system and the car ran a LOT better. Do a search relating to 'desmogging' 'smog' and you should find it.
When it comes to modifying anything, you have to remember that engineers (I'm one by the way) always design under a set of compomises. You sacrifice high end hp for low end torque, or hp for fuel economy, hp for reliability, reliability for cost, etc. The design is a function of the desired ballance. If you decide that the emissions of the engine are no longer an issue, you can certainly adjust that ballance to increase fuel economy, hp, torque, weight, whatever you chose to tilt it towards.
If you don't buy into the idea that a 1500cc midget is a set of compromises then why did they go to the 1500 engine in the first place since it drastically reduced the speed of the car, or if you don't believe that, then if not for cost, why are there no cam bearings??? there's plenty to improve on these vehicles.