If you get the ones with an offest (LCA) (I'm not sure what year but that's what they changed) then it will give you more camber. That's pritty much the main difference. Keep in mind that if you get an older bushing, it may have been manufactured way back when, Rubber has a tendancy to become brittle and crack over time. Should not be a problem at all if they were kept in a sealed plastic bag.
M3 bushings will be much stiffer, which is definately good. Urathane bushings would be much better than M3, but be aware that they CAN cause a funky creaking noise. I guess if you lube it with a urathane friendly oil, it will go away. Just something to consider.
Don't get delrin if you plan on staying on the street, that shit's hard as a rock.