A 30M x 30M track is okay for EP Racing. Asphalt is better than cement so if you have the budget for asphalt, then I suggest go Asphalt. I attached a layout of one of our outdoor asphalt tracks in my area, dimensions are 30M x 30M with 4M wide lanes all around. We found it to be perfect for EP racing because we can have alot of lay-out options. I hope this helps.