You should be able to use the 8v harness for starting, charging, temp guage and warning lights. The 16v harness was for idle valve, full throttle enrichment and ign timing through a ecu. If you are dumping the injection for carbs, no idle valve, throttle switches or cold start injector. Keep it simple with a mechanical advance distributer and ign amp,( polo or saab?). I have not fitted these distributers in a 16v, so cant offer any advice. There is a slight problem with the ht leads and the brake master cylinder with this set up, you have to use angled plug ends or cap with side entry leads.
Steve.