RE: HL engine sound question...
Yes it will workwith any of the Heng Long boards. Then you will need two 9.6v packs(i run 600mah which should give you a couple hours of sound at least).As far as a speaker you'll need a 15watt 8 ohm speaker and your all set(welsh dragons sells a nice one in a nice sealed box for $50) thats small enough to fit into just about any tank..