You do not mention the year but Maddox rollers are made in Italy by CRG. I don't know of who the Dealers are in Australia but if you do then send them the serial number on the kart & they should be able to tell you the year of manufacture. Because of availability of parts & resale value I personally would not buy this kart. It would appear from the advert for this kart (on Gumtree) that you have already bought it so why ask?
Sorry Kenny but there was a Maddox kart with X30 on Gumtree yesterday marked 'sold' but it is not there today. There is a Maddox kart with X30 & trolley for $3100 at Yangebup W.A. which seems good value.
$5500 is to much for a second hand kart & motor (no matter how new it is) but I suppose in W.A. you don't have much choice without freight. Good luck but I still wouldn't buy a Maddox kart for the reasons above.
I think you will find a cheaper option come up if you're patient. I've seen some bargains pop up in WA. And as Richard says, you will probably find a brand which will have been parts support etc.
What i'm aware, the shop that did bring the maddox chassie into australia doesn't deal with them any more.... so no-more Aus. dealers. But been prodused in the CRG factorie most parts can still be used off the crgs, like stubs, axles, steering parts an brakes
Cool..... will be nice