i had bosch 4 tip installed and last week i found a good liana mechanic for tuning - who instantly threw them out and installed brand new stock plugs..he cinfirmed me not to use these 4 tips in liana atleast ever...
my car previously was a ff cng with that injector wali cng kit...but the first owner threw it out and replaced with the local one...and it has clocked 112000km and still the coils are company fitted genuine...no issues whatsoever...
only the kit inside the bonnet is changed and cylinders (double) are intact and beautifully company fitted still.
cost of change of kit only is approx 15k here in khi...(heard somewhere)