i was wondering how to wire a push buttong switch in a 99 sunfire gt and also how to do a aftermarket tach meaning what wires would i tap into thanks

push button isn't that hard, but you still have the theft system to worry about, if your goal is to remove the key switch it can get difficult. a push button would be as simple as finding the lead to the starter and wiring it through the push button. I'm not sure where the wires are but i believe you will need a signal from the coils to make your tach work. if you find a service manual for your car you should be able to find wiring diagrams, and then the correct wires you need to tap to make it work.