Knowing B4RS a little.
There is very sound advice here with a 19t motor.
If it was that motor you ran at Batley when I was there there is no way it was a 10t, though I can't remember what it was I remember it's a budget speedo and their ratings are very often optimistic unless you want to run them on the edge.
19t motors are a great balance between speed and reliability, you will also have to do little maintenance and what you do have to do will help you learn.
Get either a checkpoint or a V2 (angled brushes) style 19t motor. For the money you'll HAVE to look second hand at ebay. Don't stress your equipment too much by trying to get anything too fast. Those ribs won't handle it for starters
