I have been racing the GT8 version for 6 months now and I have had some one-way issues on the two speed. They have slipped or failed . I love the way the car drives and have enjoyed racing it. This past weekend I noticed that suddenly my diffs are tightening up by themselves. I tore them down and didn't see any reason for them to do that. I'll keep working with them to see what's causing this . Not coming down on the car in general it has worked very well. I have the local track record with it and have shaved nearly .5 second off my lap times with my Inferno. If anyone has had these issues , please post up and tell me what you have done to correct this or let me know I'm not the only one experiencing this.