Nice review. But hold on - 80k? Who told you that? Tata vehicles get sequential injection kits that do very well in 43k all including an additional ECU and all that jazz. I'm not half as techie as wolfinstein the CNG guru!
But all the same, good to see your experience.
Please do keep running car on petrol every now and then. old open loop kit in m800 (dont recall if it had timing advancer or such) used to have issues of fuel pump drying up, and regular issue with alternator. On new kit, 22k km done by brother, no issues - lambda really rules. its just a 5k additional cost btw!