Sorry for you man, but I can tell you that in Belgium it is easier to get a COC as in France, way easier...
You have now problems because your car wasn't 100% ok at the first pass, this kind of frustrated people can be veeeery boring when they see some issues.
Even if you get some lower suspension and you still have more than 11cm from ground, you must have papers of the springs or you must be lucky and pray for having a pass at a very early monday or be the last of the week...
You know, once you get all the specifications you need of your car (http://mkiv.supras.org.nz/specs.htm is your friend), you don't need to go trough the overal check up, just make a nice sheet of paper, they accept it without a problem in Bruxelles
You'll learn a lot with this first time A positive way to see these f**cking MOTs & COC