There's a few Ozzies with Rykers who've bought RLS Exhausts from the States Frank, and there's a bunch more who've tossed the OE Catalytic Converter but kept the OE Muffler, & both groups have been pretty happy with the resulting sound (& performance)

hyea: Not that I think either would be very successful in scaring Kangaroos, or the North American equivalent, deer!! :yikes: Neither of those animals really pay much attention to 'approaching vehicle noises', not even those ultra-sonic whistle thingies that've been shown thru numerous studies (including some Aussie University & Road Traffic Research facilities) to be basically useless at scaring animals off the verges!
That lot aside, the really isn't very much at all that you can do to an OE Spyder or Ryker muffler to change it's sound &/or performance output significantly. The exhaust on these BRP 3 wheeler thingies are fairly complex sound boxes that are effectively impossible to 'un-stuff' or 'punch the insides out' of readily, and even if you do decide to go so far as splitting the whole thing in halves lengthwise to gut it & re-weld it all back together again so that it
looks the same as an OE muffler, just without the insides so hopefully with less noise suppression, it doesn't really work too well
unless you gut the Catalytic Converter anyway!! :gaah:
So RICZ's suggestion is actually a pretty good one; and one that's been used by a few Ozzies already! :yes: There are a few home grown Ozzie Cat Eliminator alternatives for the Spyders around, but I'm not sure I've seen any for the Rykers (yet?? :dontknow: ) You might want to check on the local Forums - OzSpyderRyders.com or spyderryders.net.au are probably your best bets, but there are a few others where you might find some helpful info. :thumbup:
Still, I reckon your best bet to make sure the roos can hear you is to invest in a set of high quality twin tone horns, either loud electrics, or maybe a compact twin trumpet air horn (or both??!

) They DO fit in under the Tupperware, and they can be bloody loud, which comes in handy for those 'other' animals we often encounter on the roads here Down Under... and I don't mean the furry marsuipial wombats either, but the term 'bloody wombat' has been used to describe these others quite often! :banghead:
Over to you! :cheers: