prospec all the way i have aprospec and my friend has a xb8 now they are both cool but the prospec kicks its ass on the track {we both have the sam rb WS7 racing engines} and off the track the durability of the prospec is good massive tripples at my local MX track ive had it for 1 year and nothing has broken exepct 1 proline rim not the buggies fault but nearly every time my friend has a bash hes mostly repairing it first it was a C hub suspension that broke so on....... with the xb8 you are paying for craftmans ship like most things made in eurpoe {BMWs MERKs} when we put it together everything just fell into place and fine detail is put into it but its not in for the bash anyway pros race with mbx''s and 777's well hope that helps with your choice you can talk to mugen and xb8 owners at forums on there websites to get a finer description and stories by