Need some help evaluating potential buy of a modded 1990 240sx

Spikuh

Thanks for all the replies so far guys. Just wanted to give a quick update and ask a few questions of you all to help educate myself better.

I spoke with the owner through e-mail yesterday and asked a few general questions. Found out that actual car has around 135k miles on the frame, so not bad considering mine has close 197k... Also found out that the tranny is the SR one so I believe the engine (which he said was in his 180sx previosuly) to also be the SR20 and not the CA18. I sent him another e-mail today and asked him to clarify just to be safe. Also asked if he did the install of these modifications and what sort of experience he has with this, how hard he drives the car, if he has a comprehensive list of all the mods, and if he has a recent dyno chart he could provide (said it was "freshly tuned").

Anyone have any suggestions for other questions that might be pertinent?

Anyway, now for my real questions for you guys.

I read it has a cusco 2 way differential and did a quick google search to find some info on it. It appears to be a racing differential (although no idea how good, never done the mod thing before) and I understand the basics of how they work, but I don't understand the difference between a 1, a 1.5, and a 2 way... Even after researching it a bit, I still don't understand the differences, so would anyone mind explaining for a poor fool?

I noticed he has a 4.36 gear setup on the car. A stock ratio of my '91 is 4.083, so I am assuming that this means gearing on this car is 6% taller than on my car?

And my last question. Is anyone able to make some sense of the engine modification part? Its mostly in this part:

It appears the engine is also modded, but I know so little about the actual guts of a car, anyone mind clarifying?

I know this isn't a 240 forum but hopefully you guys can help me with these general questions.

Once again, thanks for any help.