@onthehonda; yes it makes difference on xpenditure 
and decision would be your's. and it depends on the compromise your ready to bear.
it's economical, but you have to compromise over pick; you may lose it 20%.
initially i lost only 5% to 10% approximately but that was effecting CNG consumption.
so i opted for for economy over performance. now pik iz 20% less but i am getting good CNG average.
you have to conscious while selecting CNG, emulator and advancer. As all should be original to perform well.