Buying Silvia Help

im looking at buying a silvia 89 to 92 model preferrable SR20 auto non turbo or watever. What type of things should i be lookign out for, as in problems. Are there things that i shoudl know about first b4 i get buy this car. Things that i should look out for. I live in australia so the cars speedo is in Kilometers. does the sr20 engine have problems with excessive kms. wat range should i be looking at as in Kms traveled ive seen 92 models that have onyl done 90Ks i dotn know how many miles that is but ive also seen some that have done 130kms. is that a worry, or should i be only looking at the ones with less ten 100kms. Help me out i really want to find a good car except i dont have any back ground info on silvias.

thanks