Hi Knez, i just finished converting my FG baja comp 4wd. It is not an easy build. There is not a lot of room between the motor and the radio plate. ther is a company in germany here is a link to their site
http://www.onefive.de/shop/
My self i would have done a leopard but when i bought my Baja the new leopard had not come out yet.
I am using a Leopard 5692 motor and castle hydra Ice HV on 8-12s
I have only finished it yesterday and not had a chance to run it yet. If you design your own mounts for the motor you will need to remember to raise the motor higher than the center line of the lay shaft or it will hit on the rear belt tensioner housing. Also be careful how you make your battery tray. You will need to mount your motor and than pick your batteries according to the amount of space available.
Let me know how you go