i plan on doing a 520 conversion. and all i got galfer wave rotors waiting to be put on the rims.Since everything is going to be off, you should do a 520 conversion and get a bit more low end zip. Would think twice about using a vortex sprocket, where quickly and are bottom line crap. I went with this kit from HardRacing and have been happy. http://store.hardracing.com/cart.php?target=product&product_id=17804&category_id=541
Remeber when doing a 520 your speedometer and your odometer will be slightly off depending on what gearing you get. A Speedo Healer is the answer to correct that. http://www.healtech-electronics.com/
Marchesini are the shit, I hope in I will be able to pu them on all of my future but bikes. And yes like capa112 said you can use stock your stock rotors.