Two part numbers are listed when I look up which shock to order (rear left driver). How do I know which one to order?

 

Do you have an R3? One of those must be for R3s.
If you have to choose, may as well get the R3 ones, they're a bit tighter. Not if you're replacing just one though.

 

Standard suspension is Part No. F190-28-700A

R3 and special Bilstein is Part No. F197-28-700A
START DATE END DATE NOTES
03/14/2008 A (F197-28-700A) W/SIDE SPOILER-LARGE - 080314
03/14/2008 FE1** -400059
03/14/2008 A (F197-28-700A) BILSTEIN MAKE W/SIDE SPOILER-LARGE - 080314
03/14/2008 FE1** -400059


be careful, because the springs and resulting ride height may be different if you only swap one or the other rather than both springs and shocks together.