I dont recomend cutting into the wires.. The cars security system might go nuts, then you would start having issues like some of these other people there is a wire that goes into the factory radio for the alarm system called the K wire.. I just learned that this weekend from my not so friendly local VW dealer, my aftermarket (Blaupunkt) radio was keeping them from downloading the data from the car's computer (check engine light was on). I had to run out there and pull it! So, what I recomend, is that you go to
www.ebay.com and buy a wiring harness.. They are abundant for your vehicle on there, and they run about 7 dollars. Or,
www.crutchfield.com, I dont know if they ship overseas or not.