If the tank doesn't say smoke and sound (S&S) it probably doesn't have the RX-18.
For other parts, I would give Erik at Imex a call. He can sell you the very nice steel gearboxes, metal tracks, and sprockets for a good price. He's often on this forum, and will probably drop in. Plus, Imex/Taigen is stateside, so shipping won't be bad.
If you plan on upgrading the suspension to metal, tankarmy.com has been the better place for me to buy from. A warning, the metal suspension and wheels are heavy, and the tank will need to be braced, so it won't bend and throw tracks.
Feel free to read through my Pershing thread. It was also my first tank, and it's my favorite.
http://www.rcuniverse.com/forum/rc-t...-pershing.html