Buy old C70 with gas system?

Hello Forum. On behalf of the customer, a dealer sells a C70 I 2.4 liter 170 hp petrol with 177,000 km. It is a Prins gas system installed, but I don’t know when (will ask me at the dealer’s office on Monday after the date of installation). So I assume that the system is about as old as the car. I don’t know about gas systems, nor about Volvo’s idea (run an Audi A4 B5) and would like to ask what to pay attention to here. How much money will I have to put in the car after the purchase and in the next few years? Is it worth it? I can’t spend too much money on reperatures.