I have a Losi 8T with a Tekno kit and will be waiting for the arrival of another 8T. Of course I'm converting that one and the best one looks like the Tekno V4.
It is a little more expensive ($34 more than the Losi kit) but its specifically designed for the conversion. Not just a battery tray and motor mount.
It has a complete chassis with driveshafts and the truggy kit even includes a rear chassis brace.
But its cheaper than the Losi kit and Elite motor mount that others have recommended anyways.
Its your nickel.