Its not really the cost in fines or the testing,its changing everything back to original and de-tuning the car.
Altho in saying that you dont have to change it to standard,most mods are allowed as long as it passes emissions,and if your car
has been extensivley modified e.g cams,top mount,plenum,injectors,etc,it will be close to impossible and will be up for big bucks,as im goin through this right now,just considering throwing a standard motor in just to pass this B.S