What would be a reasonable price/trade for this kouki

[tamazx]

http://phoenix.craigslist.org/wvl/cto/1699449374.html

Hey guys, I posted about this on the 240 general discussion forum, but didnt get too many responses so maybe i'll get some more advice here. I found this 98 kouki with 250 k mi on a KA. The seller says it runs good and body is good. What do you guys think would be a good price to pay for this? He also seems to be interested in trading for my stock 90 N/a ~ 153k ,5 ,2+2 z32. He just sent me an email and asked hoe much money I would offer extra with the trade of the Z. He says in 2 or 3 weeks he'll be converting it to manual transmission, so he wants to know what I would offer as is, and after the conversion.

What do you guys think? how much extra should I offer if any?