I wouldn't suggest replacing only the RF strut. Do all four, get the alignment once and you'll be much happier. Plus the old spring vs new etc. May make the car sit funny etc. On the cost. Anything under original ride quality is what I'd recommend, the Raybestos ones appear to be about $90 each. Personally though, Raybestos is known for brakes, not struts. I'd go with teh monroe or moog.

PS and degreasing. It would help if you had the passenger front tire off.