I have just replaced the fuel fiter in my i30, interesting job.
As I do not have a service manual, I had to improvise on the method.
1. Remove pipe between turbo and air box. this also includes the breather to the rocker cover.
2. Diconnect plugs from filter housing.
3. Disconnect fuel lines by pressing blue buttons on each side and sliding off.
4. Remove the four 12mm nuts holding the heat shield housing to the firewall. Remove housing.
5. Remove water sensor.
6. Undo the two 12mm bolts from the heat shield. This allows you to work on the filter.
7. Change filter.
Instalation is the reverse of the above, and don't do what I did and forget to tighten the nuts before putting the intake pipe back on.
I hope this is of some use.