My Closing Thoughts on the Matter...
I Echo Gimpster's, SteveSonic's, laborsmith's, and RIZNOSS's opinions.
Common sense seems to prevail on this issue.
However, that said, here's where the argument hits the road:
1) I do not have the technical expertise on today's cars especially when it's in the field of electronics. It seems new cars now-a-days are rolling computers and we all know the quirks computers can have. This really came to reality with the Toyota's "stuck" gas pedals. Toyota may have reached a verdict on the matter, but I'm still not 100% sure ALL of the incidents were from "stuck" pedals.
Airlines even say to turn-off your electronic devices before and during take-offs and landings (which is currently under review). While many people ignore this, I heed their warnings because I'm not an expert in this field and would rather error on the side of safety.
Now there's a report on Chevy Cruze's catching on fire that's caught the attention of the NHTSA. It may be nothing… but who knows? Could the Sonic have some "bugs" down the road too? I certainly hope not.
NHTSA investigating Chevy Cruze, Jeep Wrangler over engine fires
2) I had the Operations Manager specifically tell me his own personal concern for the record. I've known the men and women at this dealership since 1999 and they are some of the best you'll ever meet. Believe me, if Butch felt there was nothing to be concerned about, he would have told me. Granted, he works for Chevrolet/GM, but now that it is on the record, if something should happen where hooking up a third-party device to the OBD II may come into question, I don't have the money to go and hire an attorney to challenge GM's decision. Especially if it voids my current and extended warranty.
3) I may be a minority, but I like OnStar. It may come short in not offering an in-dash screen base nav systems for ALL GM cars, but for what it does offer (especially in a crash-response and theft incident), it was one of the reasons I picked GM.
I really do like the Diagnostic Information that I get from OnStar. It's very thorough and it impressed the heck out of me! When I found out my ScanGauge II prevented OnStar from accessing that information (as long as I had the OBD II port occupied), I wanted to see if there was a way to restore it without removing my ScanGauge II. I now know that I can't.
4) I'm pretty sure I can still get gauges (Water Temp, Oil Pressure, and Voltmeter) for my Sonic through VDO and just have them hooked-up to their corresponding sending units (albeit, Voltmeter you just need a 12V source). If that still somehow messes up OnStar, then I'll cross that bridge when I get there. The thing is, I don't HAVE to have these gauges… it's more of a "want," not a "need."
The Bottom-line: I depend on the experts that know my car's equipment. If they say, "Not Advisable," and gives me their reason(s) as to why, who am I to say they're wrong? I have a lot invested in this beautiful automobile and I want peace-of-mind knowing GM will be there for me to cover any problems or issues I have while I own this vehicle.
I thank everyone for contributing their thoughts and opinions on this subject! :banana: