hi n assalam o alaikum guys n my VTI issue has been resolved, today I just took everything from it out which belonged to the CNG including the wiring, CNG tank and its all accessories and before that I took it to honda and get its engine and throttle washed up and now its just doing amazing, so one thing is for sure that CNG even EFI will dump the prosmatic civic, it works good on manual civic but it would really dump the prosmatic one .. so guys there is an advice if you wanna get CNG in your car then never ever buy civic prosmatic, I have seen CNG working very kool in Toyota XLI and GLI, so if you want a car with CNG then GLI will be your best choice over honda ..
but my VTI is really doing awesome now ..