Im with Crawler, If you drive a skyline a good alarm is a must. Black wire, battery backup, 3pt immobilisation, shock sensors NOT JUST glass break, pager... ect ect...
and if you MUST have a timer get it built into ur alarm module don't have a standard pen gredyy or apexi one. Its giving the theives everything they need in coloured wires nice and easy to get to.