STS best 3 port motor is the D12X (3 port) , the D3R is the most common and best bang for the buck from the STS line.
The 5 port motor D12X comes in a 5+2 port format. The D5R is the 5 port version D3R.
With the new JLR motor it makes budget on-road motors like the STS pretty pointless. Especially since they come no where near the performance and or quality of the JLR.