A quart every 750, especially for the mileage is not bad. The early 103s had deficient valve guide seals, which were upgraded in production in late '88. Do you know if your valve guide seals have ever been replaced?

You should have a leak down or compression test done. If the numbers are okay and you don't want to spend a couple of bucks a month for oil you can have the valve guide seals renewed for about $300, which might reducea oil consumption by half, but there's no guarantee. Is it worth it? Your choice.

Also look at the following nearby thread:

http://www.peachparts.com/shopforum/showthread.php?threadid=83721

Duke