For the 205/65R15 tires, the sidewall is 133.25 mm tall, whereas the
215/60R15s, the sidewalls are 129 mm tall, so the 215s are 4 mm shorter
. . .not much. The greatest differnce you'll feel with the 215 upgrade
would be better cornering/handling/braking etc. The ride may become a
weebit more harsh than you're used to, not much though. It would be a
nice upgrade IMO.

CD

My '91 has the 205's standard, but I upgraded to 225/60R15's rather than the
215's.  The diameter on the 225's was closer to the 205's than the 215's, so
my speedo was not off at all.  It should fit very nicely inside the wheel
well.

One important factor in doing this is to know the width of your wheels.  The
'91 GXE had 6" wheels, but the SE (what I have) has 6.5" wheels.  You can't
put a 225 on a 6" wheel, but you can on a 6.5" or 7.0"

As a general rule, the less sidewall you have, the better the handling will
be, and potentially the harsher the ride will be.  In practice, both of
these effects will be minimal when considering a 65 vs. a 60.  It really
won't matter until you get down to 50's and 45's.  But, in this case, it is
far more important which tires you choose rather than what size you choose.
Good 205's will outperform cheap 215's or 225's.

Another thing to consider is upgrading to 16" wheels.  They will probably
outperform any 15" wheel you choose.

Bill G
'91 SE Auto
225/60R15 BF Goodrich Traction A/T's