Hi and WELCOME to the forum!

First off let me answer for Evan (Cruzinquick) before he gets a chance to. "The 178 pulley IS the fastest pulley ever! No one can beat me and my 178 pulley!" LOL!
I believe there is some truth to his answer of the smaller pulley being "faster" than the bigger pulley. Reason? Bigger pulley, more boost but not necessarily more power because of the extra heat produced from compressing the air intake.
I think that for street use you get more out of the bigger pulleys because your boost comes on sooner (lower RPM) where you spend a lot of your around town type driving. However with the bigger pulleys you are spinning everything else faster and bearing life could become an issue.
Personally I'd go with the bigger pulley and take 70GT6's recommendation and run the pulley saver kit just for added protection.
Either way you go you've still got one hell of a car!!
Enjoy!