a great upgrade from the kit part. i run this on a tamiya f103 and it is a direct fit,( don't use the base plate supplied, just mount to your t-bar) which is good if you can't get the original. you do need to get the bearing carriers separately if you don't have them already. 3 racing do an alloy set which looks ok but may wear too quickly if you run an alloy motor plate but would be good with this gear casing. would give this 5 stars if the bearing carriers were supplied with it.