Thanks for the appreciation! Sorry for the extremely late reply, I've been stuck in some crap lately :(.
Its on CNG bro, from day ONE and kilometer 125th on the ODO. Took it out of Rawal Motors and got the already purchased Landi Renzo installed.
Bro, nope, I haven't noticed the 0-100 time, ever. I have a heavy foot, but that's in my own way, not about touching the rev limiter in every gear. Though I don't feel it to be sluggish in anyway, acceleration is a goodie like it used to be in her virginity days. I give tough time to 1.8L motors on GT road, usually what you can do on GT is 120-140 kph and that's a piece of cake for this car.
What I feel, is that it sputters a bit in climbing, on petrol, with 4 people and luggage. The reason is a clogged fuel filter and weak fuel pump. I get that changed and the injectors cleaned, it will be back in its glory for sure.
I am using ZIC A+ till date, genuine oil filter and air filter. The invoice price back in April 2008 was 985k Rs, with registration and CNG, it cost us something around 1100k. Add those alloys and a few other goodies, 1150k. 
And yes, this is one strong car for sure, just keep it maintained the way its meant to be, and it will serve you a lifetime. Experience a hand.