Starter Kill, need Bosch 30 Amp relay

You are going to have to interrupt the starter power source at some point to wire in the relay. I understand your reluctance to cut into the existing wiring and create an unsightly connection. My suggestion would be, if you have a neutral safety switch connected to the transmission, you could disconnect one side of wiring there and wire the relay in-line at that point. Another option would be to disconnect the starter wire at the back of the ignition switch and wire the relay in at that point.

Most of the relay switching applications can usually get by with a relay that does not use a diode, but I would try and find a relay that did have the diode already connected for this application, or any relay connection that is hooked to the alarm brain, so that the alarm is protected from any electrical kickback when the relay coil power collapses.

For a starter kill circuit, I normally would not use a relay plug connector if I was using a relay which already came with the diode build in, however, you could use a relay plug connector that already has the diode prewired to it and then you could use the standard 5 pin bosch relay, which would be easier to replace should the relay ever fail.

I order my relays from Parts Express, but if you only need one, I would try your local audio or alarm installion company, I'm not too keen on using the relays that most of the local auto parts stores. If possible, try and use a good quality brand relay and you shouldn't experience any problems down the road.

http://www.partsexpress.com/webpage.cfm?did=7&WebPage_ID=3&catid=47&ObjectGroup_ID=31