I'm not sure there is a best brand. OS, K&B, Fox, McCoy, Thunderbolt, Enya, etc. are all good. It only matters that it is the right heat. If its the wrong heat range the engine doesn't have as much power or doesn't run well, and the plug may not last long. Generally the midrange plugs of an engine manufacture match well with their engines, but may be a bit hot or cold for another. So start with the same company's plug if you can.