The B8 will be a completely revised version of the M1-B.
I believe you could buy all the parts needed to update the troublesome M1-B to a B8 spec.
One think you cant fault with teh TM products is its quality though always top notch.
Problem with teh M1-B is they didnt do enough r&d out on the tracks and made changes as and when the issues came up.
My M1-B has been modded a bit but is one of the quickest accellerating buggies i have ever driven but has diabolical over steer.