I managed to negotiate a deal with my insurance company within 3 weeks of the crash.
Just after I got the cheque they cancelled it as the engine had died in the interim and it seems they weren't keen on my removing the RS bits from it, despite being given permission by the assessor.
I cancelled the claim and went straight after the third paryt at fault. I then had to speak liase with another engineer and he agreed to write it off but allow me to keep the salvage that I then sold. This time it took 4 weeks from the date the assessor saw it.
Both times the agreed value was based on the market value of the car. I helped this by providing adverts that showed similar cars. It was important to do this based on the rarity of the RSX.
Should only take them 4 weeks or so unless you get into a big argument about the value. If you reported the claim quickly there's not excuse for it taking more than 14 days to inspect the car, engineer's report should be with them within a week and an offer made within a further 7 days. If you haven't had an offer by then, ring them up and bug them like hell. And like Adamantium says, if you dispute their valuation, clippings from Autotrader, jap car mags or printed off threads from our For Sale section will help to support your claim.
Depends how much you argue about the amount they give you and assessors reports etc. A month is quite long enough for the first cheque. Always turn around and say the first payment isnt enough because its virtually always below the cars true value.