When I started making components, I was very careful to do all components evenly. For many seasons, I had every component improving at 11% Department Time per race (12% for monocoque). Each component took longer to become 'good', but it meant I've ALWAYS had 100% stability.
In two more races time I should have 'perfect' components, with decent reliability, ultimate aero & cooling, and spot on 600kg weight.
I'm making my own pitstop calculator, into which I can put my pitstop times and fuel loads to work out my strategies even better (Kevs was a bit out of date, suggesting pitstop times some 10 seconds slower than I actually have). Once I ironed out a few problems I'll release it (as an Excel file) for everyone, but don't hold your breath).
After that it's down to my drivers more than anything. I need to get some newer, younger 100% all-round drivers. But with Auto-Renew there aren't many out there. Does anyone have experience with the driver training thingy (Scouts, training)... How long would it take to find a driver and make him awesome - money isn't an issue.