thinking about going to CNG

[otherguy]

Hi I have a 2000 Pontiac Sunfire and a 2003 Hyundai Sante Fe. Are there kits available for these vehicles. If so where would I get them, are they are hard to install?? What kind of cost am I looking at?? Can you switch from natural to regular gas with these?? Basically any information you can give me to get started would be great.

Thanks!!!