[Oldsman]

Far as launching hard, well it depends on your traction. Normally at the track if you launch at like 5-6k and you have slicks you'll probably break something with fwd. if you launch to low like 2k then you'll more likely bog off the line. That is what test and tune is for. Depending on track temp and tires and how sticky the launch pad is going to determine where you launch. On average when I have raced with a manual on street tires and its a fwd around 4k was not bad. Even 3500 was decent.

As for downshifting, I have always engine braked. Coming up to a light start downshifting keeping rpm under 3k. I drove my Hyundai for 168k on the original clutch with engine breaking. It does not hurt your car if done properly. Now where people have problems is riding the clutch too much when letting it out or not revving rpm up to about what they will be when you let clutch out for the next gear. Which when people just push clutch in and downshift they will normally ride the clutch more.

My previous clutch vehicles got a min of 75k on the original clutch.

The hardest thing on a clutch and will make it go out the fastest is riding it or burning the clutch. This is all amateur mistakes that people make. Which is why a lot of people don't downshift and engine break cause they don't know how and was never properly taught.