Engine performance increases with ignition advance. This is true as long as detonation (pinking) doesn't appear and, in fact, the ideal working point of the ignition timing is the one that makes the engine work at the pinking limit. There are adjustable timing sensors, and the right setting can be found in a rolling road session, but there's an easy and costless system to increase a bit the ignition advance.
Just invert the two wires coming from the angular position sensor. That way you can gain between 3° and 4° of advance. The explanation is that the sensor is inductive and it gives one positive and one negative voltage peaks. The module uses one of them, the second (I don't know if that's the positive or the negative, but checking with an oscilloscope is not difficult) and ignores the first. If you invert the wires, the positive becomes negative and vice versa, so the module ignores now the second and uses the fist one.
One way to do it clean and smartly is to cut with a small screwdriver and a lot of patience the little guides that prevent the connector to enter reversed and then just reverse it! The only problem is that unless you cut another external bit, it won't be able to use the standard support, but some plastic clips can do the job.
It could be psychological, but I think you can feel a little difference int the 4000-5000 r.p.m. zone.
Phase 2 cars, that brought Renix RE209 ignition module, have a pinking detector. These cars are harder to suffer pinking as the computer module retards the ignition timing when it detects it, but take care with the pre-ignition. It produces very strong forces into the combustion chamber that can damage your engine easily by breaking a spark plug isolator, for example. And take into account that pre-ignition at high regimes can't be heard because of engine noise.
The better, evenly and quick the fuel-air mixture burns into the combustion chamber, the better performance. And one important point into the fuel ignition system is the spark plug.
The standard set (Champion N3G) is of enough quality and works well with a 15000 km change. But you can give a try at performance spark plugs. Multiple electrode sets are probably better (I haven't tried myself yet!), but don't be confused by some advertisings. Turbo engines need platinum electrodes to last more than 3000 km and cope with turbo pressures, and the standard Splitfires, for example, aren't made of platinum, so they'll wear fast, and even could drive to worse problems. I think Splitfire makes platinum sets too, but I'm not sure. Bosch and other makers offer multi-electrode platinum sets.
When changing the spark plugs, be careful. The surrounding of the head thread is usually very dirty, and those particles might enter through the spark plug hole while removing or refitting them. The best solution is a rough cleaning before undoing them.