I have never had those quality problems with the three Fly cars that I had. The Ferrari F40 was used to race in the GT class at our club until the chassis finally gave up. With the Joest Porsche we had less success in the LMP class. The upgrades we did to them were new motors, axles and gears from Slot.it and a full set of wheels from Slotingplus. We have ultimately replaced both of these cars with a Slot.it Nissan R390 as an LMP and an NSR Audi R8 for the GT's. The motor configuration of the Panoz prevented it from competing at all. So, as racers, they do need a lot of tuning, but to look at and race with on your home track they are great!