There is a reasonable amount of information on these bikes on the Trials Oztralia site in the tech notes forum.
http://www.trials.com.au
I'm sure Girlrider has given you good advice - its always nice to get an opinion from someone you know.
This was the last of the Rotax engined Scorpas made, and they were reasonably competitive in their time.
There is only one of this model in NZ, and the guy that owns it rides in our club. He has been very happy with the bike, and it seems to get around the sections pretty well. I rode the bike very briefly, and it seemed to steer well with good power.
These bikes always seem to be very cluttered to me, with a very heavy looking engine, so I'm not sure how easy to maintain they would be. It would be wise to check up on parts availability from the US distributor as the brand has now moved to Yamaha engines.
With second hand Trials bikes it is usually very easy to make them look nice and shiney for selling, as the plastics are cheap to replace, so its best if you look at the mechanical things such as the bash plate and sprockets and airbox to try and see if the bike has been abused or not. Its also useful to find out who the previous owner was, and try and find out what level they were riding the bike at. The top expert riders have to get over some pretty big obstacles, and I'm sure it doesn't help the bikes reliablity in the long run.
Trials riders always seem to be very vocal about the brand of bike that they ride. Take some people's opinions with a grain of salt, as the most noisy always seem to be extremely biased, and willing to overlook any and all faults with their bikes.