for a limited budget stage 1
all i would do is
service car
good oil
std panel filter
oil filter
fuel filter
install stage 1 map
then enjoy the car
once you have time and maybe a bit of money
look at
removing the cat
replacing the back box
blanking the EGR valve
the car can breath very well at stg 1 levels with the std air box and filter
the forum has exellent resources in the guide section on the different tunes of the HDI
enjoy your car
all i would do is
service car
good oil
std panel filter
oil filter
fuel filter
install stage 1 map
then enjoy the car
once you have time and maybe a bit of money
look at
removing the cat
replacing the back box
blanking the EGR valve
the car can breath very well at stg 1 levels with the std air box and filter
the forum has exellent resources in the guide section on the different tunes of the HDI
enjoy your car