The Tekin will be easier to return if anything goes wrong, and it is a lot smaller.
I don't like the Tekno conversions personally as they tend to flex around the motor mount area which can ruin the motor. The Elite-RCD mount is very good, but pricy. RC-Monster do a conversion kit for the MBX6, which has a battery tray that the ESC can sit on (pre-drilled for the RX8 mounting holes).
The 2D, 1.5Y etc is the winding pattern used. Generally, a Y-wind will be lower KV, higher torque than the equivalent-numbered D wind. I would suggest the 1900KV motor for more controlability on a loose or small track, the 2050KV for normal track use - this would be most versatile, or the 2200KV for large or high grip tracks, or for bashing.
Which batteries are you going to use?
__________________
|