Is the stock clutch good enough? - It should be
Will there be a lot of traction issues? - Yes, I highly recommend 305 rears or even 315 because of your added power.
I will probably change brakes and coilovers..any recomendations? KWV3, Moton, and Ohlin, are all good candidates for coilovers. As for brakes: Brembo/AP Racing/StopTech