definitely go electric - I've seem oil temp/pressure gauges fail, it's not pretty, or nice trying to clean up oil from interior/inside the dash.
 
Re. VDO or autometer - I'd say VDO, they're used in a lot of OEM applications and appear to be good quality, have a few options to choose from - Having said that Autometer seem to have a massive following; I think it comes down to personal preference - VDO for a more understated (classy? boring?) look, Autometer if you want everyone to know you've spent a lot of money buying gauges 

Mrskylighter

100% use electric gauges.

In my old car I installed a Defi Din gauge under the stereo which blended in with the rest of gauges in the car. (Same colour green backlighting etc)  
The Defi Din has two temperature gauges and one pressure gauge which you can use for whatever you like. All the senders are electrical.  
Pic below is the same I used.



I used it for coolant temp, oil temp and oil pressure but would work just as well with your gearbox fluid temp monitoring requirement.

It does cost a premium though, but is a bolt in (To the dash) solution which looks quality and is quality.

I think I bought it through Dylan (Gorilla Ind.)
 

MrSkylighter, am very interested in the DEFI gauges (have been looking for a quality 'clean' gauge option for a while) - did they fit in an SW or AW?  Is the din dimensions the same size? 
 
Dudeman, electrical all the way.  I love my Omori electrical boost gauge.

MIDN1T3, yep the Gauge is one DIN in size. Fits exactly like an aftermarket stereo does. Same mounting hole options etc.
 

MIDN1T3

Mrskylighter

100% use electric gauges.

In my old car I installed a Defi Din gauge under the stereo which blended in with the rest of gauges in the car. (Same colour green backlighting etc)  
The Defi Din has two temperature gauges and one pressure gauge which you can use for whatever you like. All the senders are electrical.  
Pic below is the same I used.



I used it for coolant temp, oil temp and oil pressure but would work just as well with your gearbox fluid temp monitoring requirement.

It does cost a premium though, but is a bolt in (To the dash) solution which looks quality and is quality.

I think I bought it through Dylan (Gorilla Ind.)

MrSkylighter, am very interested in the DEFI gauges (have been looking for a quality 'clean' gauge option for a while) - did they fit in an SW or AW?  Is the din dimensions the same size? 

Dudeman, electrical all the way.  I love my Omori electrical boost gauge.

esskay

Re. VDO or autometer - I'd say VDO, they're used in a lot of OEM applications and appear to be good quality, have a few options to choose from - Having said that Autometer seem to have a massive following; I think it comes down to personal preference - VDO for a more understated (classy? boring?) look, Autometer if you want everyone to know you've spent a lot of money buying gauges 

Reddtarga

Body length of all VDO gauges I have seen is 45mm + 20mm extra for the connectors = 65mm deep overall
I don't think one would fit very well in stock temp gauge position in the fascia even if you could squeeze it in because it may sit too far back.
I got my VDO gauges from a local supplier here in Geelong Vic, 'Gaugeworks' and it only took a couple of days for then to order them in.
I think the style I have  is 'cockpit vision', and I chose PSI for pressure, and degrees centigrade for temp.

With VDO stuff there are so many different types (black face,  white face etc) with different scale calibrations in metric, or imperial so you have to be careful what you order.
That would apply to most different brands of gauges as well, and check face diameters as well as depth because some of them vary a lot

Google is your friend to find out more on this stuff and don't buy anything till you research it thoroughly.

 
Its a pretty much non-bling car so i'll probably stay with practical things, not to say AutoMeter aren't the goods, just a bit more dazzle for $. If I were to go Autometer (really is the easiest looking option right now, no replies from VDO dealers in Sydney) i'd go for the 'Cobalt' range, in metric. Definitely analogue gauges, not into digital.
 
The VDO 'International' range look pretty smart...
 

 
I have been trawling forums all over the place looking for reviews, its going to come down to whatever is the better price VDO/AutoMeter.
 
Will try and persevere putting a new temp gauge in the factory gauge spot, I have an old cluster which I can cut the back out of so here's hoping it fits in nice.
I'll give it another few days waiting to hear back from local VDO dealers, may have to go USA but will make sure measurements are metric.
 
Thanks for the opinions.

Forget the mechanical gauges unless you were referring to a boost gauge.
 
mechanical gauges are illegal to have inside the car, hence you see muscle cars with scuttle panel mounted gauges.