EC5 connectors seem to be one of the best
http://cgi.ebay.co.uk/EC5-battery-CO...item518fe71d9a
Got some from this person on ebay all good other day.
Looks to me like you have too high KV motor there for 4S? I read around 30,000rpm is the sweet spot 41,440rpm seems alot, 2000kv for 4S by my reckoning?