This pertains to the 2011 & 2012 FJ coils and likely any others color coded the same:
I measured both front coils with a digital caliper (removed coils from the front shocks) the taller one is Purple/Grey, so it's the driver'sside---the Purple/Orange one is the passenger
The driver's side very "top" coil is also much thicker than the passenger side last coil on top---top is being referred to as the coil end that is rounded, not the pointed or flat end of the coil
I made several phone calls today and researched this like crazy as well...everything shows that the UCA's from an FJ are also a direct swap for our Runners, not beefier or better just an OEM direct swap
I will be changing mine as soon as my rear coils come in a few days. I am installing the FJ UCA's, front/rear coils and shocks and will likely install new sway bar bushings too. Will update after everything is done.
"Anyone know if one rear coil is longer or firmer for the driver's side like the fronts are? Both have the same color codes, but I have not received them yet to measure them.