I've had both on my car and prefer the 178 crank pulley BUT the installation is a bear/expensive/problematic. The supercharger pulley can be swapped on or off in 15 minutes or less which is a huge plus. The 178 makes more power than the 65mm pulley but it's close enough for some to call it a wash. The 65mm pulley is the easy button. I switched to a 178 with the PSK because my 65mm started rattling like a snake and I knew it would explode sooner than later.

Les