krokodyl

Hello every one, I just rescently recieved a caldera 3.0 and am now wondering what really makes the earthquake bigger. I was looking at the earthquake 3.5 parts and noticed that almost all parts are comatible with the caldera. (not counting parts of motor or exauhst) The chassis seems the same size ( tell me if i'm mistaken here). So now i would like to know how to make the caldera the same size as the erthquake and all parts that make the earthquake larger. I know that it would've been cheaper to start with a earthquake but it didn't occur to me at the time. Thanks for any help.