Question: How much EUROS per more-hp is actually calculated like this? What is the most cost-effective method for saying 10 – 20 hp power increase? It’s about my Colt C50 1.5 (12V) with 90 hp. Is actually already a correct car at about 10kg/hp. I just installed a sports suspension 40/40. Sport air filter supposedly doesn’t bring anything except sound, does it?