Hertz LIS
Had booked one of the smallest car categories available (A - Opel Adam or similar, 2-3-door, manual transmission) for a 10-day one-way from Lisbon airport to Faro airport, and was upgraded to a W Category (Special, Economy Elite). Ended up with a three-month-old Mini Clubman One with automatic transmission and about 4000 km on it. Very happy with the upgrade especially given that Hertz Portugal is a licensee. For any Gold members renting from Lisbon airport, you can go directly to the garage and there is a dedicated counter.