i've noticed at the shops that the cheaper alarm systems don't
come with their own relay (they utilize the existing one), the
expensive ones do. does anyone know whether this factor is
important?
hmmm... actually the relays are used as starter kill. As long as you can get the starter kill, regardless whether expensive or cheap alarm, they are the same concept so should be okay.
If you haven’t already seen enough of these how-to help cards for personal hygiene amid the pandemic, here’s one for cars interestingly, sent to us by the good guys at Proton, a Public Service Announcement for all...