I have 3 of these units, starter, ultimate and recently I purchased the advanced and they are amazing however the ⅜ parts for the advanced backbone aren't as easily available as the ¼ in stores so you may have to order direct from jungle hobbies. If that's the case you could end up with wrong parts in your order and no reply to your email about fixing the issue. But like I said mistking is great! Just buy the stuff for it from local stores so you get the right stuff :)