Speaking of a Killer Shark
http://mcspeed.homestead.com/Photo_Album.html
otherwise setting a narrow tire out wider only makes it look sad. My
guess is that those that turn around might be thinking the opposite of
what you think they are.

Yes, you can cause problems.  What are you trying for, the ricer look?
Skinny tires a foot outside the car?

First, the front end is dependent on where the tires sit as to rubbing and
hitting. The stock wheel is 8"x15" with 4-3/4" backspacing.  With a
255/60-15 tire, the inner fender required trimming on '79 and earlier and
not sure about '80 and up.  The factory trimmed those optioned with the
255/60-15 in '78 and not sure if they trimmed some, all, or none in '79.

Placing that same 255/60-15 on an aluminum wheel 8"x15" with a 3-1/2
backspacing (much safer than spacers) means that it rubs when turning in the
fenderwell at the back.

On the rear tires, this places the tire 1/2 to 1 inch outside the fender
which gets things chipped and dirty if you are driving and not just sitting
and looking.

Spacers are bad on the studs, placing much greater stress than designed.
Corvette uses a 7/16 stud stock.  In road racing, C3s during the '70s and
'80s used longer and thicker studs to prevent loss of wheels. Typically the
5/8" x 3" Moroso studs where used.  It is generally recommended in racing
that NO spacers be used, however, they are not banned, but tech will usually
shoot you down as unsafe for any over 1/4 inch.

Mid America Enterprises (and others I believe) used an engineered
spacer/adapter to mount C4 wheels to the C2 and C3 cars.  HOWEVER, these
spacers where necessary to fill the extra backspacing of the C4 wheel, so
the basic geometry of where the tire patch center was did not change.  These
were also a high-tech aluminum alloy designed for strength and used to bolt
to the hub and then the wheel to the adapter, not merely a spacer.

So much for just the strength issue, now to design and safety.

Go to a BMW drivers school, one where they spend a day in class showing BMW
design videos and driving techniques, not just a "show up at the track and
drive".

You will find that BMW has researched the suspension geometry in much depth
before many manufacturers ever discovered that life existed beyond 1/4 mile
driving.

The location of the center of contact of the tire patch is very important to
safety and handling. It is hard to show without drawings, but imagine a line
from the upper pivot point to the lower pivot point.  In the case of the
1980 Corvette, upper ball joint to the lower ball joint.  Now extend that
line to the ground.  This point is the ideal pivot on the ground.  The
further outside or inside of that point a tire patch center is, the more
force a tire exerts on the car to turn left or right.  In normal driving,
the left tire balances the pull of the right tire, however they are
constantly fighting. The further the center is from the point, the more they
fight.  Add poor adhesion (water, oil, sand, snow, etc.) and you suddenly
have a car veering off the direction you wanted, i.e., ditch, oncoming
traffic, etc.

Have a flat, and you have a violent pull to one side.  This is the very
problem that Ford had with the flat tires on the Explorers.  They were
designed for a tall tire and so when it went flat suddenly (blowout),  the
tire "moved" the contact point further from the ideal pivot point and there
was a violent pull that took the driver by surprise and, combined with the
high center of gravity, flipped them.

The Corvette, being much lower, will not suffer that flip, but you could
find yourself suddenly off the road or into oncoming traffic.

In summary:
1. Spacers over 1/4 inch are a very bad idea.
2. Corvette does not have excessive fender room to accommodate offset tires.
3. A wider tire and wheel combo, with proper backspacing and offset, with
achieve the look you want and remain safe.
4. Wider tires and wheels will put a strain on the suspension, and the weak
point is the studs. Enjoy changing the rear ones. :-)