Evil Plan to foil cat thieves, need a little help (skunk cat defense system)

I had my catalytic converter stolen got new ones, (and yes I'm in cali grrrr) Cut and put in a self made version of the cat security kind of plate.
Might just go over to the place in east LA that let me use the lift and add rebar to all the pipes (as in weld it on)
and I might just make some security screws as well. (A shop in sacramento actually makes those custom by welding wheel locks on the cat bolts).

all nice and great, but I would like to do something else, use an arduino (well the chip (328p) and a gyro chip to create another alarm, add a radio chip to notify me, and hack a "glade or wick" fragrance pump to spray skunk essence or something similarly foul stinking if they tilt my car more than 5 degrees for more than 10 seconds (to avoid trucks or earth quakes setting it off) of what it was 1 minute after the car was turned off i.e. parked. At first was thinking of an ultrasound detector first but that might be set-off by a poor cat.
But I would also like it to set off the regular alarm as well, since it only goes off if the doors or hood opens, I was wondering if I could fool the car into believing the hood was opening? Anyone know how the prius detects the hood opening?
What you guys think about turning my car into pepe la peu?
terramir
PS: on another note, I once saw a post on someone who created a third generation type energy/power meter, for the second generation prius, but I searched for it I think I got the vocabulary wrong on this it has bars and tells you if your close to starting the engine how much your regen-ing etc. it's in the odometer display on the US 3rd gen and someone hacked together something like it for the second gen prius. Anyone got some links or what it's actually called, cause I can't find the relevant posts.

 

Well besides all that unhelpful info, because yeah driving without a cat is a crime, anyone got any $.02 to put in about the hood detection or anything else mentioned above?