Having had quite a bit experience with remote starts, I'll give you a basic run through.
1. The industry leader is DEI and their Viper/Clifford brands. They have the best accessories and integration/installation amongst the other brands. In addition, they have the largest dealer network so the lifetime warranty you get can be utilized should you ever have a problem in more locations than other brands.
2. The dealer won't be bothered by the remote start with regard to the warranty. The Magnuson-Moss Warranty Act prevents dealers from voiding warranties for aftermarket equipment unless the equipment itself caused the failure. Yes, this same law SHOULD protect you from the dealer voiding your warranty for using a tuner, and technically it would, but it would take a legal battle with Ford for you to assert your position and prove that the tuner didn't cause the problem. In the case of a remote start, however, it doesn't raise engine performance, it doesn't stress components beyond what they were designed for, and they're so common that even dealers themselves sell them.
None the less, I think your feeling about having a professional installation is spot on.
3. As far as a recommendation for a product goes, I would recommend the Viper 5901/Clifford 50.7X, if you're wanting remote start with security. If you're just wanting remote start, the 5501/330.3X are stout models. Both feature rechargeable remotes which is far more convenient than older models which chewed through batteries like a savage.
4. Find a legitimate independent installer. AVOID places like Best Buy and the like. They have a tremendous amount of turnover with installers coming and going all the time. Independent shops generally have installers with far more experience and attention to detail which is what makes or breaks the performance of any aftermarket equipment. I dont know if I'd go with Ziebart. Doing some research online and finding a legit independent shop would pay dividends in the end.
5. Feel free to ask any questions you have.