If your spring has been used for a wile i would also recamend getting a new one It dose make a very big difrence. I would only get the Kyosho 4d spring don't get the kyosho hard spring the "4d clutch spring is much better". I also think you should try the settings above they may be to agressive for you but i sugest you try them and see how it feels to you. I would also recamend ritching the bottom end. As i know when i came from off road into onroad i thought i had my clutches worked out. But it took a very good friend and very exprenced on-road racer to give me the advice i needed. At the time i was useing a sirio21 wcr engine and the clutch was coming in way to early and boging the engine down and robbing power from it. After i did the changes he told me to do I found that i had leaned the engine to force it to make power because the clutch took so much away. After i ritchend the engine with the new clutch settings the engine came to life instantly i felt ezy a 20% paformance boost and don't get me wrong the engine was very very fast befor. Clutch is one of the most important settings to get max paformance from any engine rember that. Best Regards jeremy.