James
Only reason cars are breaking currently is because people didn't repair them. We have too many spare parts, currently the wear rates are that low it costs 4-6parts to repair 2 cars every race or if you leave it the cars can do 6races before you need to repair them. So why not push them to the limit and burn up a lot of spare parts?
They can factor in weather with them rates too car wont fall apart unless you turn up at Spain with 0 design points in Reliability and Research wont let that happen. People that are lapped will be doing less laps nobody can do more laps the equals percentage is the total amount of wear for maximum laps for the tracks.
Thanks for sharing the % but there's no guarntee that people that people would use the % in your calculation plus the one thing you are seeming to forget is "What about the new people?" That's the major problem and sorry if I sound like an antagonist for you but the new people don't have the surplus that you have to burn through! I am pretty much against this only because what you are proposing makes it so that pretty much no new people can join since after a couple races they have no parts to repair their cars, if they can't repair their cars they break, if they're broken they can't race. To me sorry but I am against this I can't support a system that may cause IGP's downfall.