car theft prevention tricks for manual trans. Any ideas?

Hi, anyone have any ideas on how to prevent manual transmission 2005 Jetta TDI from being stolen. I don't like the idea that the manual trans can be shifted into N, steering wheel locking mechanism broken and just simply pushed away. I once saved my 1990 250D Benz with a hidden push button switch that was installed inline with the starter circuit. So any time I wanted to start I would have to press and hold the button when turning the key to start. I was bored and did this installation to kill some time, and just 4 days later my M.B was broken into, steering wheel lock was broken and piece of something was stuck inside of my ignition switch which was rotating 360 degrees. I have couple of other things on my mind but would like to know if any of you actually did something regarding this problem. I was thinking about some electrical valve inside of the clutch hydraulic line that would not allow pressure pass unless the valve is energized by hidden switch but I don't think that would last long since the pressure would be so high. Anyway anyone have any ideas that would like to share I would appreciate it. Al