The sintered rotor will give greater drag brake effect naturally and feel more like a brushed motor, as a result you can turn the drag brake down. You can kind of get this effect with just more flashes on the drag brake with the bonded rotor but it’s not quite as good.
You will get MUCH stronger brakes off the sintered rotor, at least as good as any brushed motor, I sometimes turn mine down as they are too much.
The sintered rotor makes the speedo run more efficiently so you get more performance and run time (not massively noticeable) but the speedo runs MUCH cooler.
The bonded rotor looses it’s field over time, much more so than a sintered rotor, so by putting a sintered rotor in (assuming the bearings are OK) it will feel like a new motor again and stay like that for longer.
If will work perfectly with an older GTB, just turn the drag brake down to 2 flashes else on the bonded setting 4 flashes or whatever) it will try to handbrake on every corner
