Only what I've read. Odd thing, many modders seem to prefer beginning with the 250 rather than the 300, but I'm not sure why. I need to find out if both the 300 and the 250 have the same mounting plate or arm board pattern. If so, I think I'll order another arm board cut for it from Mr Scillia. I'm sure at some point I'll go rega. Regards, Russellc