RE: Steel 5 1/2" rims vs. 6" Alloy rims.
Late last summer I picked up a set of factory alloys (14") and replaced
my stock steel rims.  I moved the 185R14 Agilis over to the alloys.  I
didn't expect a 1/2" difference in rim width to make any noticeable
difference, but it did.  With the alloy rims the Westy is just a hair
better riding, a hair more stable. The difference is suable enough that
at first I thought it might be my imagination, but I've become convinced
that there is a positive difference.  Go figure...