I can only speak for the RCPD convestion since I don't own a tekno.

as noted made in the usa, less things to convert and break (direct bolt on to stock chassis), big battery tray 52mm x 170mm, all Jconcepts and AE bodies work with the conversion, trick one piece battery tray and mud/rock guard design, works with tekin, castle, neu, feigeo, novak, and medusa motors, RCPD has been in the 1/8th scale market longer then RC-M and tekno. RCPD (DJ1978 is his user name) is small a company with full design and machine shop on site so if you want any custom work done he can do it. He's currently doing a custom conversion for me right now just look under the post he start for a lot of his work..

Electric 1/8th Scale conversion kits.