V70 III 2.0F LPG conversion: BRS or Prins?

Hello, when looking for a new Volvo station wagon and considering whether diesel, petrol or gas I am still not at the destination. Depending on the purchase price of the “refurbishment base” gas is very advantageous and probably a little more promising than diesel. But I don’t want to start this discussion now… Anyway, I found this offer: https://suchen.mobile.de/…/270360518.html?action=parkItem The 2.0F should be gas-proof(er) if not released by Volvo. Offer for a BRC Sequent 32 and a Prins VSI-2 available. Price difference approx. 400 Euro incl. valve additional lubrication. Does anyone have a recommendation or does one of the two systems know? I calculate with a consumption of approx. 10.5 liters. Is this realistic? Thank you, Johannes