i would suggest OZ superleggras for a strong, lightwieght 17.
you will probably lose a little acceleration no matter what if you go to 17s unless you spend a hell of a lot of money for a very lightweight forged rim.
but you also get better road grip and control as well as some sweet looks
going to a decent weight 17" rim isn't going to make you slow. you will just loose a little acceleration thats all. its not like if you run a 15.7, you will now run a 17 flat. its not that drastic..but there is a lose.
just throw on some engine mods to make up for it.
i suggest going to 17s and lowering the car....the feel is incredible.