Would try to make this short and easy for all the readers here
All Euro IV cars should get the injection system(sequential) systems in there cars, however in some of the cars(very few) the conventional systems works but not as good as it should.
Cars with Euro III and Euro II norms can go in for conventional systems as it is quite light on our pockets.
Go for good injection systems. Please do ask, recheck, search online for only approved CNG kits, Look and ask for the company’s certificates/ approvals. Don’t get into traps of dealers as many of them uses certificates of other companies to get your car endorsed on RC and put a unapproved system on your vehicle. don’t make decisions in a hurry do your research well and then go for the systems.