I wouldn't worry about the spark plugs. They don't get that tan color with the new gas alcohol mix like the old days and will tend to look lean with the Motronic. Also, you had the air leak plus the rings and valves settling in. The next set will be a better indicator. Make sure you break the rings in well. Along with varying the rpm, drive down hill and use the engine braking to help them seat. A compression and leak down will give an indication how things are settling in. Here is a picture of my first set of spark plugs and the results of my first compression test.
