Crystals and connector help please

[rc10andy]

Hi, i am looking to buy some crystals to get more into racing and i havent a clue what to look for and what to pay for them. I have had a quick look on Ebay but i dont want to start bidding until i know what im talking about. I have the Associated trigger style handset transmitter.jpg like this one. I will also be upgrading it soon so are crystals universal?

Also, i am wondering what the best battery connectors are as im using tamiya connectors and they r crapo!!

Any help much appriciated
Andy