I would recommend the BT-45 from experience. I had them on my Ninja a few years back, I also ran the Sport Demon once but ended up changing it at the first opportunity. It just wasn't up to the track day work.
I did over 40,000km's on my Ninja250 during the time I owned it. I knew guys who raved about the sport demons but I have to disagree. I did track days (The sport demon rear let me down on one occasion

) I also raced it once, finished 3rd place all day. The BT45's got the stick and they last well too, I would frequently Ride Napier to Wellington on them. I would recommend to put a BT45 on the front to match when you come up to replacement time. Seriously it's another $15... That's 2 visits to the pie shop

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