First of all not many people steal Volvo's. Second the ignition is hardened and difficult to punch out. But if you are still worried you can secure your car on the cheap. Go to Radio Shack and get one of those round key electric switches. Hide it in the interior but easy to get to. Such as in the consol. If you don't use your cigerette lighter you can get a small push on push off button switch and place it in the lighter socket. So all you would have to do is push in the cigerette lighter to turn it on and off. Wire the power for your main fuel pump through the switch. $15 in materials.