sounds to me like he dont want you to hear it before you take it, maybe knock the price a little on that hes not being very helpful in his own sale.
from the pic thou, the rest of the car does look quite clean and sound.
**Free plug for silviagod.**
also i personally would put the extra money to this car below, the guy selling it is prolly one of the most honest guys in the S12 community, and he does know the s12s well, i would say if hes selling it as a good car, then thats what it is. and its running.
http://www.nissansilvia.co.uk/vbb/showthread.php?t=1739
**EDIT** i just saw your post
he did say he knows of 2 others.