roadrat

its noticeable from 50mph to 75mph and only on certain roads.

took the car in to have the tires balanced, but the guy showed me that the left two
WHEELS are out of balance (slightly bent / warped), not the tires.

previous owner must have hit a pothole.

Is this something that can be repaired?

adfsouth

I don't hear of this often with Porsche wheels.....they are typically known to be very strong. I would start by taking them to a different shop for a second opinion. It really sounds like the tires are either out of balance or out of round. If it really is the wheels, you can usually find cheap OEM replacements on ebay or you can use it as an excuse to check-out some of these.....

http://www.wheelenhancement.com/index.php?t=Wheels

(make sure to scroll down)

gota911

A good wheel shop can repair sligtly bent wheels.

sclemmons

I have used Ye Olde Wheel Shop for damaged BMW factory wheels years ago. I believe they are in Maryland but you may want to contact them first to be sure they are still there. They came back like new.

Edgy01

If I knew where you were I would suggest a few places, but since I don't I can't. They can be gently fixed.

dgcate

Had the exact same thing happen, turned out to be my right front wheel..

Both wheels can be straightened in just a few minutes. My local Porsche dealership contracts with a wheel straightening service that comes to their shop to straighten wheels on site from the back of their truck where the straightening tools are carried.. Easy job. They staightend Porsche, BMW..all kinds. Your tire guy should know someone. Or look in the yellow pages.