I have done VEMS PnP on two Porsches:
1. 1992 Porsche 964 Carrera 2
2. 1994 Porsche 993 Carrera 2 TPC supercharged
Both have twin-plug engines with 12 plugs and they work fine with VEMS logic-level IGN OUT (1 required for 964, two (dual-out) for 993).
964 has switch-type TPS (manual gearbox, Tiptronic cars have variable TPS). MembersPage/PeepPaadam