mister2
Don't know why you're all so convinced there are no tyres left  in the correct SW20 profile for 16" rims. There's these for starters, which are rated really highly:
 
http://www.yokohama.com.au/Tyres/ADVAN-Neova-AD08.aspx
 
 

They don't seem to list rears: 235/40/16. Is that a tyre you can get on the black market? I'm going to go with 225/40/16 if I end up getting the 16s (I much prefer them over big Amish wagon wheel 17s)

 235/40/16 isn't the correct size for an SW20 on 16'' rims. It will give you the wrong rolling diameter, which will put your speedo out and give you a harsher ride. 
 
The correct size is 225/45/16 for the rear and 205/45/16 for the front, though you can also use 205/50/16 on the front if you prefer. I use 205/45/16 myself.

mister2
Don't know why you're all so convinced there are no tyres left  in the correct SW20 profile for 16" rims. There's these for starters, which are rated really highly:
http://www.yokohama.com.au/Tyres/ADVAN-Neova-AD08.aspx

The Neova's are expensive. $244 - 205/50R16 & $269 - 225/45R16, $1026 to do a car.
Throw another ~$200 at it and you could be rolling around on race rubber for that kind of coin.

I looked into T1R's, but despite being listed as being sold in the required sizes, I couldn't find anyone in Sydney who stocked or could even order them. I have decided to switch to 17", run a wider 215 front and 235 rear and use Federal 595RS-RR's which are only $630 to do the whole car! We've been running the RS-RR's on the GC8 and find them a great tire, albeit a tad noisy.

You should look at the prices on Demon Tweeks Knightrous. You can get any of the tyres discussed above a lot cheaper than OZ prices – even with shipping from the UK. Last time I ordered tyres from them, they were sitting in my driveway just four days after I ordered them.

mister2
You should look at the prices on Demon Tweeks Knightrous. You can get any of the tyres discussed above a lot cheaper than OZ prices – even with shipping from the UK. Last time I ordered tyres from them, they were sitting in my driveway just four days after I ordered them.

225/45/16 are AUD160.78 ($321.56 pair)
205/45/16 are AUD146.34 ($292.68 pair)
$614.24 for the car
/ObamaNotBad
 
 

I would 'buy local', but not when I can actually get the tyres I want, in the sizes I want, at those kinds of prices  

Where are those rsrr prices from Aaron?

My rays were on the car when I bought it 15 years ago. I run a 215/40/17 on tein super streets. First set fulcrum ever sold :-D

5SGTE
Where are those rsrr prices from Aaron?

St George Tires.
Federal 595RS-RR
215/40R17 = $152.50
235/40R17 = $159.99
 

I get them too from St George Tires:
 
Federal 595RSR RS-R
215 40 17 = $142.50
235 40 17 = $127.50

Carmikey
I get them too from St George Tires:
 
Federal 595RSR RS-R
215 40 17 = $142.50
235 40 17 = $127.50

Me Too....