I had a lot of good reliable performance from my HPI Flux 10.5, so would recommend that. It worked very well with the boost settings on my v2.1 HW speedo, and took a lot of heat and speed without complaint. I sold it on and the new owner was also pleased. (I gave up 10.5 as a 12th class, no other reason to sell it).
I've no experience of the SP motors, so can't comment.
