Hi chap. What temperature is your car running at?
Does it get to 90 and stay there even when on the move?
Thermostat sticking open is quite common. My last car was a 1.4 ABD, know your pain

The 13" sport raders were a factory wheel on the match iirc.
If you want to sharpen up the handling a bit, stick some 15" wheels with lower profile tyres on, get it lowered on stiffer shocks and springs. It will never be a sports car but they can still be a giggle. Drilled airbox and filter will give a bit of noise that at least makes it sound a bit racier