I'll go along with Bigifig on this. A modified collector's car is worth less
on the market than an original. Sometime the mods are minor, such as different
wheels, radio, pulllies. These can replaced if the owner kept the original.
When you get into mods, such as headers. rebuilt heads, trans, suspension. The
value is gone.
With that said, the 89 turbo are a hot collectors item because of it's built on
the last of the Buick turbo V-6s. Were and always will have high value if kept
Now, if your looking to invest. Your better off buying stocks or bonds. For
example, the 1979 Trans Am 10 year anni. 4 speed sold for about $ 12K if you
could find on then. Today, on E-Bay, a perfect low mileage example will go for
around $ 25K to $ 28. If you less out the storage costs to keep something that
big for 25 years, Good investment? Up to you.
If your looking to have a fun car to drive, look at the late (98-02) F-bodies.
A buddy of mine just picked up a Z-28 6 speed in red with 35K miles that looks
show room new for $15K.
Its up to you. One last tip. Something people think what they have is worth
more than what it is. Its up to you.