1st post- hi guys!
I have installed several alarms systems (mostly DEI) since 1993, including remote start- 2 of which were on manual transmission vehicles of mine. I designed an interlock that disabled the remote start if it was in gear and/or the parking brake was not engaged- worked just fine. It usually takes me an entire weekend to do an installation because I'm rather meticulous about how the wires are bundled/wrapped and I solder/shrink-tube all wire splices.
I just purchased my '99 silver C5 coupe (auto trans) a few weeks ago and I have a nice Clifford remote start system waiting for me to install. Having never dealt with bypassing VATS before, I decided to research a little and found this thread. It sounds like one of the arguments against installing remote start in a C5 is based on electro-mechanical relays, which are pretty much a standard part on every modern vehicle. Every alarm/remote start I've installed employed several relays and none have ever failed or activated when they weren't supposed to. They do have some drawbacks vs higher cost solid-state relays, but if diodes are wired across the coil and inline, voltage spikes are absorbed and feedback voltage to the alarm brain is avoided.
Another argument is the VATS bypass. If the wiring is done properly, the bypass is only in effect when the remote start system is active while it activates relays to mimic the ignition key switching. Since this is all that's going on, knowledge of the timing and communication between vehicle computers is nice, but unnecessary. Inserting the key and turning it isn't any magical sword-in-the-stone experience... it's just throwing switches and remote start uses relays to mirror that action.
I still haven't heard anything convincing enough to make me not install remote start, but I will gladly debate it if anyone has good info. C4C5, your knowledge of the machine is not being questioned here. I can see how a bad experience with a poorly installed and/or malfunctioning system would cause me to recommend against them in general. I intend to post an installation thread detailing the experience and hopefully bust some myths. Probably not until this heat wave passes though.