Welcome to HTS!
Can you post plots from your winISD sim and/or the driver file you used? In addition to basic T/S specs, an estimate of the cone's surface area will be enough to simulate cone excursion as well. What you describe sounds like a winning combo, 500W isn't unbelievable for a good 12" sub. Some car subs model okay in HT, others do not. It just depends on the sub.
Another doubt I have is what you are doing for a port and the associated port velocity, you'll need a big port to go that low and that loud and avoid port noise and/or compression.
Can you post plots from your winISD sim and/or the driver file you used? In addition to basic T/S specs, an estimate of the cone's surface area will be enough to simulate cone excursion as well. What you describe sounds like a winning combo, 500W isn't unbelievable for a good 12" sub. Some car subs model okay in HT, others do not. It just depends on the sub.
Another doubt I have is what you are doing for a port and the associated port velocity, you'll need a big port to go that low and that loud and avoid port noise and/or compression.