yea... i would never recommend anyone replace shocks one at a time...

especially on older cars, where the other three shocks are pretty worn, and you got a fresh one that probably doesnt have the same bound/rebound rates.

id suggest you either get at least another new shock for the other back side, or just replace em all...

and did you say $60 for an OE replacement shock? you know u can get tokicos or AGXs for like $70-80 right? might as well upgrade em all. if nothing else, it will ride a lot better. (esp. with a 2" drop)