Hey everyone, first thread!! 
The names Bryce.

I've recently been looking into and designing a dash cluster that would be able to have all the gauges necessary in the actual dash cluster instead of mounting them on the pillars and such. I've got nothing against it, just not my style to have them all over the cabin.. I like things to be kept tidy, but also still give a sense of awe. 
Anyway, to the point! I've chosen all the aftermarket gauges that I would like to use. But because I would actually be replacing the stock cluster. I would need to work out a way to keep the warning lights and things like that.. Can anyone shed some light on my situation? 
I've heard a few different things like, 'Regardless of if you're replacing the whole cluster it'll still be plug and play.' And then other people saying, 'You'll need some sort of custom circuit board to wire everything up to..' Blah blah blah. Obviously it seems MUCH more logical that I would need a custom circuit board.. Or even a modified circuit board from the original cluster. But I'm just after some straight facts!! 

Any help would be highly appreciated! 

Cheers.

/Attached is a VERY rough design, just to see what it will sort of look like. 
I am aware that the speedo is a 260MPH and not KPH, but I do want the 260KPH variant and that was the only non-animated image I could find in a rush :p

I'd try and keep the original blackout part from the original cluster and work the new gauges into it.
 
That way you could keep all the warning lights and circuits - which are good enough anyway and would be a major nightmare to get sine fine work done / do such fiddly work.

Do you have a cable driven speedo or electric? If electric will it work with the speedo you wish to use?
 
The factory dash has circuits built in to it to spit out a speed signal to the power steering ECU and perhaps ABS?

I want to replace the whole instrument cluster. Which means I'll be replacing the original speedo with a GPS speedo. Doesn't need to be hooked up to a speed sensor! 

And because I want to replace the whole dash. I don't know what I need to do to make sure all the warning lights will be working. Because the factory dash has the right circuits built in.. Is it possible to modify the new gauges wiring to connect them to the factory circuit board/

I think what Widemr is saying is, the factory eng ecu and PS ecu use the speed signal from the factory speedo.  You would need to supply this signal still.

Couple of other ideas for you. 
http://www.thor-racing.co.uk/Toyota_MR2_Mk2_Dial_Kit-THOR00129.asp

You used to be able to get the warning lights separate, then you could make some led's to sit behind them. Might be worth emailing them if you only want the warning lights. Think you have to email them anyway to get it shipped to Australia.
OR somthing like 
http://www.ebay.com.au/itm/Set-of-11-Dashboard-warning-lights-with-Icons-suit-Opel-Cars-1950-80s-/390507349290?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5aec0d452a&_uhb=1#ht_3760wt_1163

5SGTE
I think what Widemr is saying is, the factory eng ecu and PS ecu use the speed signal from the factory speedo.  You would need to supply this signal still.

Can you explain why I would still need to send that signal? You'll have to forgive me if that's a stupid question. Electrical systems are still fairly new to me, what better way to learn than to jump in head first!

Meawea
Couple of other ideas for you. 


You used to be able to get the warning lights separate, then you could make some led's to sit behind them. Might be worth emailing them if you only want the warning lights. Think you have to email them anyway to get it shipped to Australia.

Those plates would be exactly what I was after! I'll definitely be looking into it. But as they would be on the custom dash and not a standard dash. I would need to work out a way to get the LEDs working as per usual. That's my biggest problem. I just cannot seem to find a straight answer!

The power steering requires a speed input to adjust the amount of assistance it is giving etc.

kameleon
The power steering requires a speed input to adjust the amount of assistance it is giving etc.

Makes perfect sense. Something I should have assumed. -_- 
So my best bet would be to make everything run through the standard circuit board?

If the ecu does not get the correct speed signal, it limits the boost and triggers a CEL error.  I experienced this after swapping gen3 into gen2 and not powering up the speed defender, which stopped transmitting the signal to the ecu.  Power steering worked but not sure if it affected its level of assistance with speed, did not test it out.
 
Cheers