Hey Gary! If it were my car I would ask a dealer about the "nervous"
feel on the road at speed. Could be the different handling, or it
could be he tires. You don't want to end up at the bottom of the lake
in a twitching car - er - in a nervous wreck. And when you replace the
tires, go with the Michelins. They are the best all around.

2.5 years ago I put Nokian WRs onto my 94 ES.

Best purchase I could have made.  I love those tires.  GREAT in the
nasty stuff, quiet and effective in the summer.

I have 35K on them, still going strong.  I'll put them on everything I
own.

I have been using Nokian WR's on my LS400 for about 3 years out here in
Southern CT to avoid messing with Winter changeover.  I feel the noise level
is a little greater than a touring tire, but certainly have no complaints
with handling.   I am not an aggressive driver, but pretty much maintain 75
mph on the highway.  I had 4 wheel alignment when installing them and they
have been wearing very evenly.  They seem to wear a little fast, but I
expect I can get ~50-60K mi on them and it sure beats keeping Winter/Summer
sets.  I keep them inflated at 42lbs front / 40lbs back which is a bit MORE
than reccomended.  For MY money/situation, I would buy them again.

Most of the Nokian models are directional tires.  What model do you
have (and what is the climate like where you live, as Nokian has
summer/winter/4-season models), and are the tires rotating in the
correct direction?

As for the "nervous" feeling, it could also be an alignment issue,
besides your thought about tires and suspension feel.  (For example,
some Prius owners comment about a "twitchy"/light steering, and an
alignment from one end of the allowed spec. to the other end usually
clears it up nicely, along with a bit of driver retraining (don't over-
correct the steering, grip the steering wheel more lightly).)

I had Nokians on my LS430 here in Pittsburgh. They literally burned up in
one season. Balder than Kojak.