OK, confirmed the ECU this evening as ME2.1 ........... Looks like I've got another project looming. I have collected the regulators and control unit to do the auto drop btw, might give this a go at the same time. I'll probably put her up on axle stands to do the testing, a bit safer lol
ME2.1 is good news. Much better than M3.7.1!
One more thing you could do. Remove the connectors off your ECU and check the actual pins you need are present.
You need to look for the following pins :
D19 ( Clutch switch ) : now here's the interesting thing. The GTV/Spider manual says that the clutch switch already exists and is connected to D19. If true, that's a lot of work already done!
D20 ( Stalk : SET+ )
D21 ( Stalk : SET- )
D22 ( Stalk : Recall )
D23 Brake switch. The brake lights are already connected to the ECU on pin D14. However, cruise requires a second independent signal from the brake pedal to D23 which is why the Cruise equipped brake pedal switch is two switches in one.
E10 ( Warning light ).
Identifying connectors D & E : Look at the ECU with the mounting lugs down. There'll be 6 connectors.
Leftmost are connectors A and B. Connector A on the bottom with 2 rows of 4 terminals and above A is connector B with 1 row of 4 terminals.
2nd from left is connector C with 4 rows of 10 terminals
3rd from left is connector D with 4 rows or 6 terminals
4th from left is connector E with 4 rows of 12 terminals
5th from left is connector F with 3 rows of 7 terminals
Connector D pin 1 is bottom left so all the pins you're looking for are on the top row. That's pins 19 through 24.
Connector E pin 1 is also bottom left. So E10 will be on the bottom row.
If that is unclear there is a drawing of the connectors in the workshop manual. You need Vol 3 part 2, 1998 model year section 55-29D ( ME2.1 ) page 6.
If all the pins are present, you can get the Bosch numbers off the ECU label and ask someone with a 166 24V in the 166 forum if they'd take a photo of their ECU. You can then compare numbers and do a bit of online research as to what they mean.