My son has a HPI Blitz with the stock SC-15 ESC and Stock Brushed Motor. What would be a good decent first upgrade. Hes 10 and drives OK. I hate to buy things twice so as he progresses I would like to just add maybe a better Stock Motor. Im sure it will be at least a year before his driving gets good enough to notice any differences or being able to handle fast set ups. I also dont want to spend the money for something top of the line. Im gonna start taking him to our local track to practice and race.