Cheers guys!! I can't wait to get some better pics of the thing, I just paid for it today so the deal is sealed.
Walkinshaw, I don't think this diff would last long with the turbo, but the plan is to get a 3.45. I consider this a tall ratio so I can still get good fuel economy on the highway. I'm only aiming to crack 120 mph.
Xrated, the EF V8 radiator has been recommended because it is the only one to combine mounting points for thermofans and the EA-ED style large outlet for the hose. I was told they are around $200-250 but haven't yet researched it properly. I'll let you know.
Arv, believe me I gave it serious thought. The simple and rugged early LS400 was the second contender but the fuel economy, good parking and (to my eyes) more attractive styling of the Eunos edged it in front, not to mention the much lower price and higher equipment level. The next dream machine is a '97 LS400, but I don't quite have 60 grand lying around here.

Hell I was originally looking at 626s and Telstars but I got greedy.
Steven you are a vulture.

Actually the coolers seem to be going for less now on Ebay anyway, I half wish I'd waited.
outback_ute and Jaeger cheers for the info! I was watching a video Mazda sent me in 1994 which pretty much says as much - the key is low compression ratio and high expansion ratio. The car requires premium but then I've always used 98 octane on all my cars anyway.
4.9, not sure about the ECU, I'll try and find out more.
VanGelder, yeah it turns out it was a bit of a bargain. I'll never forget the words of the dealer accepting my offer but saying he's "not bloody happy".

There's one in Mornington for $11k which I didn't get around to seeing, and there's one at Ringwood Car City which I was considering. The one I have bought was only the second I saw. The salesman explained that these cars are much harder to sell than VT Commodores etc because no one knows about them.
Another point of interest is that this example has done slightly higher kms than my EA, around the 185,000 mark. The other one I was considering had only done 125,000 but seemed in inferior condition and did not have full service history or one owner. I think service history is everything on a car this complex.