the standard NOS kit for 300s come w/ a microswitch that clicks on w/ you go WOT. A 10lb bottle is usually good for 10 1/4 miles passes on a 60 shot. The Jim Wolf kit is aimed for for Turbo cars and shuts off when the turbo makes a certain amount of boost. Make sure you get a gauge and RPM control...these are very critical. Zex has a very interesting setup which is controlled by its very own computer and uses the TPS for engagement. Zex does not make a kit for our cars.
