I recently converted my G200 HC Smiley Dash to one from a G201 DeTomaso for Tacho 
Pictures give more of an explanation as to what I did as all wires are colour coded
Basically, just had to move an earth or two, indicators, belts and a couple of others, not a full rewire 
*** NOTE ***
1: To Get The Tacho Working, I cut the #8 wire off from 16 pin G200 plug and attached it direct to a wire from Negative side of coil ( the red one ) to #9 TM ( P ) on 14 pin socket of G201 Dash. I Tried to use the #8 pin while still attached to loom but didn’t work, but measured 3.6 - 4.0vdc on wire with car running.
2: High Beam Light Stays On When Lights On. seems due to having a Common Negative power source on circuit board whereas G200 had a separate BEAM -VE pin, might have to cut circuit board track and solder that left of wire to it?
3: Speedo Reads Less Than Actual Speed. Tested against a Phone GPS Speedo App, Speedo reads 60kph, GPS reads 68kph 
Have also included F2 Dash Socket pics if useful 
G200 14 pin socket
G200 16 pin socket
Detomaso 14 pin socket
Detomaso 16 pin socket
F2 14 pin socket
F2 16 pin socket
14 pin plug Before
14 pin plug After
16 pin plug Before
16 pin plug After
The Result
