Got my first 240sx, help me out!!!

[silvia180SXboy]

I got my 240sx today and I need a little help. Okay, first of all, the alarm does'nt seem to be working. I locked the doors and stayed inside the car for 30 seconds, unlocked and opened the door from the inside but nothing happens. The security light blinks all the time. Also, it's a 5 lug, does that mean anything special? And how can i tell if it has LSD or abs? I'll lift the rear wheels with a jack on Monday and turn the wheels to see if it has lsd, I heard that's how to tell. My main concern is the alarm because I plan on hookin' up a system and don't plan to get robbed at school.Thanks for your help

[silvia180SXboy]

Oh yeah, i bought the car for $3,000. 128,000 miles, auto, no rust just some clearcoat peeling off, and it came with a Kenwood KDC-3011 CD deck. Also, one of the little lights next to one of the foglights is gone and three wheel center caps are gone but I'll replace those (with rims!?). Engine runs great and transmission shifts great, no power loss and pulls hard. No major dents. clean title. SE model. I think i got a good deal, what do you guys (and gals) think?