You want to go cheaper, or more expensive? KYB AGX's can do the job for under $300. You could also go with the really expensive stuff like the motivational shortened struts or something. Go check www.sentra.net and look in Kojima's garage or the parts database to get an idea of what's out there.
I agree. AGXs are the cheaper and more common solution. I still recommend the Motivational struts if you can afford them, because they have the shortened shock bodies that will give you an extra 3-4" of suspension travel.
just DONT get tokicos! I had them when they were the only shick out for the b13 chassis, and they suck. i can t tell you how many i had replaced. they were like 80-85 each, so the AGXs are such a better deal. and, they were shock dyno'ed and were the same as the 300/a piece G.A.B. shocks!