sir ji, i'll try my level best to make it work on CNG, lakin i am telling you in advace it SUCKS on CNG, it's even worse then before on CNG. Lakin petrol pay hawai jahaz bun jaye gi 
The Alto wala setup is about 5,000 for the intake and filter (If you get a cheaper filter it'd be less) 3,500 for the hot wires and 3,400 for the irridium tip plugs..
The options list goes on and on if you want it to 
Yaar custom/modified altos to nahi, stock altos ko KHA jaye gi 