Ok, so I searched high and low for ages for the cable driven TRD speedo. No luck. Anywhere. In the world.
 
So I sourced an ADM cable drive 260kph speedo, plonked it in, not accurate. It reads about 12% under from the quick drive I just had. Checked it against a gps which are pretty much 1-2kph on the money.
 
Oh yeah, its on my jdm turbo which had the 180kph jobbie. 

Yes it can. 
 
Not usure anyone in syd for you, but down in melb i recommend this mob http://www.howardinstruments.com.au 

http://forums.overclockers.com.au/showthread.php?t=1076722
 
Found this on OCAU a few weeks ago.

Thanks for the info Wide, Sqveak - not sure what you are linking to as its a 'member only' board....

Sorry about that. I forgot that it was a members only section.
 
Here's the most relevent information from OCAU:
 
D.I.Y. solution for digital speed senders.
http://www.jaycar.com.au/productView.asp?ID=KC5435
http://www.youtube.com/watch?v=bMs7w72QTVM
 

OCAU.Amneet
The other option is to get a workshop to do it. As far as I know the only place in NSW that is capable (or at least competent) is "Injection Perfection" (Link below) in Bankstown Airport. They do the testing and calibration for NSW Police/High Way Patrol. I'm not sure how much it costs though.
http://www.injectionperfection.com/

 

OCAU.BakemandShakem
Pre 2006 can be 10% either way, post 2006 can read over by 10% but not under. So speedo can read 110 and your actual is 100, but not read 100 and actual 110

 

OCAU.aznpsuazn
Advanced Auto Instruments in Revesby and Manly Auto Instruments in ... Manly.

 

OCAU.banshee
ADR 18-03
http://rvcs-prodweb.dot.g..au/files/ADR%201803.pdf
 
See page 1 to determine your vehicle type, and page 15 Annexe 3 for the calculations specific to it.

ie Passenger car is Type M1

V1 Is speed displayded by Speedo
V2 is actual speed

ADR 18-03
In the case of vehicles of categories M and N:
0 ≤ (V1– V2) ≤ 0.1 V2+ 6 km/h;

 
So at 100kph (actual) your speedo can read betweem 100kph & 100+((0.1*100)+6) or anything between 100 and 116kph.

On a bike, it can overread by up to 18kph at 100. (So you are doing 100 & your speedo indicates 118kph! (In practice most bikes I have owned or seen over read by ~10% (the odometer is accurate, though), my car, on the gripping hand, is almost spot on.)

 

OCAU.brocke8
Advanced automotive instruments in Revesby will sort out your speedo problems.

Unit B1, 77 Carrington St, Revesby NSW 2212, Australia

Phone number(02) 9792 7399

Been using them for years
There are other shops but he has been always the cheapest with a quick turn around.
And this is a licenced shop which the mods will be legal