Im looking to upgrade the sc pulley with the fixed 77mm from fabtech
Or the fabtech 180mm crank pulley
The gains are relatively the same,,yet what are the pros and cons
And have anybody faced any issues running either of the two pulley

Well , fabtech doesn't have anything and doesn't manufacture anything, the fsp is made from upd and the crank pulley is most likely ASP.

Go with the clutched 77mm which is also made by upd (shardul)

For the crank pulley installation must be done right so know that in advance. Only ASP for crank pulley.

The true diff would be ease of install with the clutched 77mm sc pulley.

This ^^ - I'm running the 77mm UPD Clutched and power output is wicked

In regards to the Fixed Pulley setup - If you want to have to data log everytime you drive for the entire time you own the car and have alarms setup for failed water pumps and high IAT's then I wouldn't go fixed pulley

I really wanted a fixed pulley but after a year of following fixed pulley threads I have gone with the 77mm clutched and am very happy with the results