I used the supplied motor mounts on mine... I did however drill a couple of 1/8 inch holes on each side of the fusalage and use 1/8 inch dowls to pin the firewall to the fusalage.. This however is SOP for me on ARF's... As near as I can figure the weakest link is the horizontal stab... I ended up sheeting mine with 1/16th balsa to reinforce it.. With the extra weight of the Mag 4 stroke the balance worked out pretty good...