Timing chain problem

Ok I just bought my first car a 93 240sx, and I am having a couple problems with it.

My timing chain is rattling around idle, I think that the chain is too loose. I have already removed the upper guide mounted between the cams by two bolts.

I am going to replace the chain, should I replace the sprockets too?
I would like to avoid removing the head.

How would I go about timing the engine?

And lastly has anyone driven with JIC or Megan coilovers I would just like to get some feedback before deciding which ones to get (i'd like to stay JDM if I can).

Thanks for all your help.

buy a chilton manual.

you have to pretty much remove the head to change the chain. while you do this, you may as well replace anything else in the area
again, get a chilton manual. it tells exactly how.

and as far as the coilovers...

JIC = gay
Megan = JIC's gay retarted crackbaby

get silkroads

I have the factory service manuel
I was talking about replacing the upper chain I know to replace the sprockets I would have to unbolt the two cam sprockets and remove the head to replace the idler sprocket
My question was to fix the noise would I be ok just replaceing the upper chain?
and whats wrong with JIC?

I'm not asking how to install the chain I'm asking if I could get away with using the old sprockets because the upper chain is the only problem. I can replace the upper chain without removing the head but I wouldn't be able to get the idler sprocket out.
I was just asking for your opinion.