1. Yes, you probably need to replace the window regulator.
2. Coil Overs are a suspension part, I believe. I am not familiar with them at all, but I can assure you that they have no relationship to the ignition.
3. The LS uses COPs. (Coil On Plug). There is one coil over each spark plug, for a total of eight. Four are on the left side of the engine, and the other four are on the right. They are more or less in the center of each valve cover, with a smaller "coil" cover over them.
4. Like the over topics above, symptoms of COP failure have been discussed a lot of this board. Do a little searching and read the stickys. Generally, you can best feel slight misfires while accelerating at moderate throttle position. Dealer's find marginal COPs by doing a stress test. If you have a Ford specific scan tool, you can do a KOER test and look at the misfire counts - that helps only sometimes.