lol... strathfield.. yeha, they have nooo idea, I suggest you do research online, find what you want to buy, then go find who sells it, and ignore whatever they say!!!
I had a pioneer rep in strathfield tell me that these two pioneer subs were the same, except the dust cap... well, one was actually a free air sub, the other was for enclosure use
this came from repco, they dont really know about car audio either, probably why they were clearing a $269 sub for $59...
did you go to
JB hifi maybe? because dicksmiths dont really sell any car audio...