congrats for the new car!
yar since you have a ff cng vehicle, most mechanics in karachi will not even open the bonnet of yr car. that is for sure.. that injectors wali cng kit inside the bonnet is not easy for them - infact considered the cause of failure of liana due to its extreme complications and difficulties in working on. best is to do it all thru a 3s..they have proper softwares for it. tappets can be done by local mechanics that is not an issue..
since you do not have any issues currently on cng, keep enjoying the car and keep going until you feel hesitations etc in engine perf