At ZDayZ earlier this year there were some 370s with over 450lbs combined passenger/cargo weight blasting through the Dragon/Hellbender without issue. The car will do fine. Obviously it won't drive like it will with just a 145lb driver in the car, so take your time to feel it out with the added weight, but in general there won't be any trouble.
Hell, we took a 5,000 lb Maxima out on the Dragon for a spirited run and it did fine!
