corrado cobra alarm

[mystic 8v]

hi,im currently fitting a cobra g190 alarm to my corrado g60 1991 ,im trying to decide where to put the immobilizer cut,the instructions use the starter terminal 50 wire but im not keen to put it there as you could just bridge the the starter and it would crank over and start.I would like to put it in the terminal 15 ignition wire from the ignition switch to the fuse box as that will kill the engine ecu and fuel pump.The ignition wire is 1.5mm thick and i just wanted to make sure that it doesnt carry too much current through the alarm,the manual states 6amps continuous draw and 20 amps for one second,i did check it briefly with a multimeter and it seemed to be under the 6 amps draw on the ignition wire,i even thought of wiring in an ignition relay and using the primary side for the immo cut?,please help if any alarm fitters have any advise,cheers