I'll sell it only if I can get the right price - am in no rush. The reason is that on balance, I've decided I would prefer an E36 coupe - M3 or a decent 328is. I can only pick one up if I sell this car though, and given the work that is currently being done on it, I'm not as eager to get rid of it as I was.
I believe it is a Nikasil block, but I'll have to double check that. Compression test was run by PO a couple of years ago and it was pretty even. I don't have a recent test though. I have only used 91 octane or higher (though I've only had it a couple weeks) and its running well.
Bimmersport went over it this week and other than a few minor things which are currently being addressed (AC drive belt, control arm bushing, front brakes, shocks), it received a clean bill of health.