im assuming your a girl (i only know one dude whos a princess and. . . . lets not get into that)
dont do a kit!! D:
get a stillen lip (
www.stillen.com ) (pics of the stillen lip on this 01 SE
www.mrsentra.net <-- thats marvin

)
and lower the car... some Koni Yellows and Progress / Eibach springs, ProKit's (i wouldnt do sportlines, too low of a drop in my opinion)
the only body kit that looks remotely good imo is the BuddyClub2 (
www.buddyclub2.com )
but you're talking $500-$800 for the kit, plus prob close to $1000-1500 to paint / install it. thats money better spent on performance stuff
instead of the body kit, get the stillen lip, lowering springs, shortened struts, a cold air intake, and a nice catback exhaust system
if you get bitten by the performance bug, you could get the Hotshot header (stay away from ebay / OBX sh*t)...maybe even go turbo like me
hot girls driving tricked out nissans = hopefully my future wife lol
btw prob should be in the Cosmetic / B15 forum... dont worry about it though. you're new, you arent familiar with the rules yet. besides, a moderator will move in soon enough...they keep up with these things.
also...check out
www.b15sentra.net/forums
good place for the 2000+ sentra owners...lots of b15-specific info.