First post, registered today. I work at a bike/atv store here in Arizona. We are looking at these new pit bikes. We have looked at three bikes so far, SDG, Sikk and the Thumpstar. We have a guy that tests our bikes, rides them hard and another that looks at quality issues and ability to get parts. Do not have final results, but will post when evaluations finished. So far, this is what I have seen so far. The Sikk is a nice bike, looks good, quality ok, fast. The SDG is a nice bike, but quality not there, some parts look pretty cheap. The Thumpstar has our attention and is the one of the three that is not well known. The bike looks good, is also very fast and by far has the better parts. This bike looks more like a quality racing bike. We have been told that a new version will be out with all aluminum body. Parts for these pit bikes is and will always be an issue, but we have been told( on the phone) by various dealers that parts can be found for all. More later, any reviews or info on these bikes and any others appreciated.