bar the remap which is a given and will transform the car have a look at MTE / Shark which people usually use. I used Demon Tweeks which isnt too far from you and still run the same map 2.5 years on and still love it.
You can look at the Focus ST225 Intercooler upgrade which I defenitly advise for track day to aid cooling.
For handling I will list the few below.
Best thing for grip is to ditch the skinny standard tires and get 235 / 40 this will make a huge difference.
For handling, if you are going cheap I would get the hardrace sway bar and eibach lowering coils. If you are looking at coilovers this will make an incredible difference in handling as well and are leaps and bounds better than the normal dampers coils ... I have the bilestein B12 kit on mine and could recommend it more.
For power unless you are goin expensive I would just get the remap and a k&N filter and not really bother with the induction.
With exhaust, if your box is rotting have a look at some jetex systems to replace yours
