need to know what is a good/longer fly time battery seen the multistar 3s 4000 and the 5000mhr 4s battery,seen on you tube right now I am using the phantom batterys getting around 15 min ,just want to know what to get I also know that I have to cut out alittle to fit I have seen also the bigger door for the battery how sells the upgraded door that is good to order online thanks I see shapeway sells them are they good to order from