Pics of the MKIII with the V8 in it please
As an idea for you though - on general 'value for investment'
6 speed TT Supras will be the area you'd want to have as a 'starting point' as it will hold it value (and Supra prices are on the up)
In terms of Colours - Silver is the most common with Black, White and Potentially red being the next popular. So for an investment, try and find an Anthracite/MSB (Brown), RSP (Blue), DJG (Green) or Yellow. But you'll often be waiting for a good one.
The Supras came with lots of optional extras which included various creature comforts as the models developed down the years, so the more OE you get with the purchase the more valuable it may be seen as.
Hope it helps.