I have a Sisu and a Merc and the only mods I did were to remove the magnet and replace the guide spring with a hard spacer. This makes them much more predictable and less likely to deslot. They seem to have plenty of traction on my Sport track, mostly sliding, but sometimes tip. I don't have any R1 turns, though. They are great fun once you get used to the massive inertia, which gives less braking than an older Carrera!?