Plug loose wrong one? So confused

I have a 2005 Pt Convertible GT Turbo with 35000 miles on it (about 20000 of which was from being towed). I am the second owner. Car started to idle a bit different so we checked the plugs and found number one a little loose and looking as if it had spark jump up the side from being loose. We replaced the plugs with the same. Noticed that number one was again a bit loose. I did some research and found that my car under hood says to use a LZTR5A - 13, RE14MCC5 plug - what we took out and put back in the car is a Champion or NGK (can't remember which) S3RE14MCC5 plug. I have been looking for hours and found mention that my car requires the "copper" plug and that the 13RE14MCC5 runs a little bit cooler than the S3RE14MCC5 plug. Is the fact the car has had a hotter plug in it going to be a big problem? Someone told me to put a drop of Loctite on the number one plug when installing and some kind of grease I can't remember what now. I have the gap set at .50 and was told it should be at .40 with the different plug. I am so confused. Is this thing with the plug vibrating loose going to be ahuge problem. Is there really that big of a difference in these plugs? Why do the books at the stores give you the wrong plug information?