This is the factory OEM line filter from Filtran/BorgW.  If you want to change your line filter this is the best filter to buy as it can catch down to 10 microns.  The aftermarket stainless steel mesh filters can only catch 100 microns. 

Due to the design of the GR6, you do not need a high flow filter for the line filter.  We have used OEM paper filters for line filters on all possible power applications and it makes no difference.  Power does not change what the line filter does as its job.  So don't buy the SS filters and risk damage to your solenoids and seals, buy the factory original filter which will catch the smaller stuff and allow your trans to live!

Video of how to change the filter yourself:

More info:

This is a data log of what a clogged line filter looks like.  Note how line pressure (ORANGE LINE) drops off and can't keep up with target (BLUE LINE) at low pressure conditions:

Here is another data log of the same unit with the line filter replaced.  Note how line pressure (ORANGE LINE) follows target (BLUE LINE) perfectly: