for 17" wheels its not that bad... there are deffinatly heavier wheels out there... and the stock rsa is actually a lighter tire then most... tire weights can range from 20-25lbs in the 17" area.... so don't forget about that and buy a nice light weight wheel then drop a 25lb tire on it and loose your weight savings...
i am now running 18" wheels with a total weight of 37lbs.... yes its a noticable difference more so in tossing the car around corners then in a striaght line but it does help in both cases...