Yeah you can, hit up an email to twobros and they will sort you out although dont expect a response for at least a week or so they are a bit slow in that regard, although you may get lucky. If you already have a twobros slip on, they should help you out not a problem.
When I emailed them, I got a response saying that there was a header already in oz and to give them a call to sort something out. Would be good if you can pick the one up that they already have here, will save you some cash for shipping. Below is the email from twobros:
We have a header system already in AU. Can you please provide your phone number so we can better assist you?
Jessica [email protected]
So just send the above through an email letting her know that you are after a header system only and if there are any already in oz and they should help you out there mate. Let me know how you go.
It certainly will give the same outcome although with a slight loss in backpressure, cut it open with a saw yourself (it is pretty easy as it is not all that thick pipe) and knock out the cat material. Then take it to a shop to get it welded back up. Make sure you mark the orientation of the pipes with a marker before you cut (I used the lines of the sides of the cat) so that they can line it up in the same spot as before. Otherwise you may have problems bolting it back up if it is not in the same position. Will do the same job as a full system, albeit not as pretty and shiny
A shop will probably charge you extra for having to knock that cat material out as it is pretty hard shit, plus some just wont do it depending on your area that you live due to legalities. If you are only taking in what is literally just a pipe to be welded up, shouldnt cost you much more than 20-30 bucks.
And careful with spraying the pipes, my mate just did his and was 1200 degree F high temp paint............. let it cure for twice as long as stated.........not a pretty sight now. Mega bubbling, burning, peeling and melting. I would opt to get them ceramic coated maybe, most places also do an extreme temp ceramic coat in black if you want to go that route.
Removing any restrictions on either the intake or exhaust will be worth it..............but only if you have a tuner to help balance the fuel/air ratio at the level that it should be with the restriction gone. Like others have said before me, I would do none of the above until you have a tuner first.
IMO doing these mods first without having a tuner will not make the bike run any better, in fact in my case it was worse. Not to mention having the motor run lean due to more air coming in, but no extra fuel to match. Lean conditions creates heat which is energy lost that is not converting to power.
And seriously a slip on will cost you still around twice as much as a tuner, for no gain except noise.