hi guys!im new on this site,and first time i have a toyota car(altezza),my model is rs 200, im happy with a power but i like perfomance, so first my thought was to fit short air intake,i have cheked most sites for proper air intake,but all very expensive,over 300£ for rs 200 only.So i have made custom one.Fit it.start a car and oooopss!!!car wont working properly,rpm to LOW,and and rpm arrow jumping,after this problem i fit back original air box,but still want perfomance air intake.WHAT I HAVE DONE WRONG?Could u guys help me with it???(air intake on picture below!)