Personally I would put a spacer behind the motor I don't feel that it is that critical. The simplicity is whats great about the shock fliers. My 330 has been run thru the mill and don't expect it to last for very long . I've been using side force generators on mine for 50 + flights doesn't take as much elevator for KE and is more stable . Its fun to fly also the gen2 Yak is great. Flew last night at the gym nobody showed up had it all to myself. Don't know why nobody showed up .