Fire suppression requires a plumbed system with dispersal nozzles at the driver and engine fuel rail (mandatory) and fuel tank (optional). This system can be push button or pull cable type to discharge the system. You want enough nozzles to be effective, but not too many as to empty the system too quick. You can find these complete systems for sale for most motorsports web sites, including the Lemons store on this site. These systems have a two year life and re-certifying is a much better option than buying new. I would recommend using a manufacturer that has certified dealer near you for recertification in the future.
A manual, point and squeeze type extinguisher does not comply with rules for in car. You may have one in the car as a redundant system if you choose.
You will need a hand held extinguisher for fueling and it is always good to have another one all the time in your paddock space.
Second question - I am under the opinion replacing OEM equipment with OEM spec is not included in the $500 budget. Make sure you have a good battery hold down. If you have one of the OEM standard bottom of the battery clamps, replace with a sturdy over the top metal strap/bracket.
1975 Chevy LUV. 1 Corinthians 13:7
1999 Chevy Blazer
