I think you'd be able to squeeze out 30HP max (reasonably) out of this motor (12000W / 80 = 150A; 150A * 144V = 21600W or 29.5HP). Now having that information, consider the following...
Original VW Beetle was 800-840kg, with a motor as little as 1L and 25HP. So for something that small you could probably do it, but... you said 1000kg before the conversion, which means you're not taking into account the weight of the batteries. You also didn't say what speed you want to achieve - if you are happy to cruise around town at speeds below 70kmh, you can get away with less power.
As for motor controller... I assume this is a series-wound brushed DC motor. Curtis doesn't make controllers over 80V for such applications, though I don't know what the 80V nominal is in terms of max voltage. Kelly has a bunch of controllers with 144v option:
kellycontroller.com
Original VW Beetle was 800-840kg, with a motor as little as 1L and 25HP. So for something that small you could probably do it, but... you said 1000kg before the conversion, which means you're not taking into account the weight of the batteries. You also didn't say what speed you want to achieve - if you are happy to cruise around town at speeds below 70kmh, you can get away with less power.
As for motor controller... I assume this is a series-wound brushed DC motor. Curtis doesn't make controllers over 80V for such applications, though I don't know what the 80V nominal is in terms of max voltage. Kelly has a bunch of controllers with 144v option:
Brushed DC Motor Controllers - Kelly Controls
Brushed DC Motor Controllers for Brushed DC Series Excited and Permanent Magnet Motors.
kellycontroller.com
