Those are some loaded questions!
First, what type of tools do you have? You'll need at the least, flat concrete surface, two jackstands, good floor jack, metric socket and wrench set, wrench and socket to fit the nut on the ra bracket (1 1/16 I think) a deep socket the same size as the whench, 6" -1/2" drive extension and ratchet as well as a pry bar, penetrating oil and a helper.
Do you have the knoledge/ experience/ willingness to tackel the job?
Are you asking the price of the part (aprox.$20 per side), or the job ($40+ parts, aprox.$100 labor + alingment $50)
Which is best, is subject to opinion. Rubber are quieter and softer (better flex) but tend to fail esaily. Urathane lasts longer but is prone to squeeking as well as causing a stiffer ride.