>>car, car wash, car seat, car window, car tires, car winshield wipers I seldom use keyword phrases, unless the phrase is the only way to cut a concept out of a herd of unrelated sites (where there are confusing terms). I can't think offhand of a decent example it's something I do so seldom.
If you leave individual words, the search engines are smart enough to take a phrase the user types in and match the words in the phrase out of available individual words. They are usually programmed to NOT disassemble keyword phrases. That means that unless your ESP is working well, you can choose the wrong set of keyword phrases while the person who just uses a string of words will have more matches. In your example, if I typed "winshield washers", the keyword phrase "car winshield washers" would not be a match - because the keyword phrases have to be an EXACT match. But a keyword string like "car tires window windshield tires washers wipers" would match because the words are pulled individually.
>>Is there ANY keyword repitition? Would I get penalized by any SE? Additionally, if I use the word "car" 15-20 times in the body of my page, am I going to get penalized for this? You might get whacked for repetition, might not, but they would not count all the "car" words and add them up for greater relevance on a search for "car" - each phrase gets treated as a distinct entity in the database for technical reasons. But overall your chances of matching a phrase search are greater with word strings than phrase strings because you don't have to guess which combination of words the user will type.