I'm planning to purchase Genboard and learn from basics. Here what I can gather so far:

I think I need:

According to the specs we could find (ME7) for your engine Volvo B5234T3 2003 it has:

Using those specs and the list you posted above (ps2 option is not practical on your setup instead wheelspeed input is much more versatile) we would recommend:

Free inputs for extra function activation are standard available on the ecu, one of these can be utilized to handle the Input to retard timing from TCU

A stepper chip for driving the Volvo 850 idle valve is also a standard feature of the v3 ecu.

Additional wiring diagram information found for this engine type on web: