It does sound like the quadrant but it could also be the result of a streched cable too, when you replace the quadrant replace the cable. Most of them come in a set anyway.
About that alternator, there will be some minor grinding to the current alternator bracket and you will have to cut one of the plugs off and splice the negative, and positve into the alternator, it will come with instructions too so I wouldn't worry, it's not that complicated. Just borrow or buy a dremel, it worked perfect for me.
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