Well I got my 4000 30 c lipos from hobbypartz and am pleased with the results. I broke one in cycling it twice at a 5 amp discharge then off to the races I went. I won the A main with it ! Has great punch . I don't think I would run one In mod but for stock type racing it will work fine. These are a little wider than a normal size so if you run a lipo tray it may be a little too wide.