Steeping grains versus mashing

My last five or so batches have been extract with specialty grain. I have found that i am trying to steep more and more grains, to the point that i am nearly doing a mini-mash.

Currently i am bringing the grains up to temp on the stove top, then putting the brew pot in the oven to keep the temperature at approximately 155 degrees.

My question is this. When i steep specialty grains, i am steeping grains that have no/little diastatic(sp?) potential.

When i add grains that have diastatic potential (like 2-row?), will the enzymes in those grains convert the starches in my specialty malts?

If so, how will this change the flavor, maltiness, alcohol, etc?

When you steep, the grains have little or no diastatic power, but they also do not contain starches. If you added some base malt (like 2 row), you would theoretically be mashing instead of steeping, but the enzymes would only convert the starches in the 2 row unless you added some adjuncts like flaked barley, corn, oats, rye; that contain starches but no amylase. Without the amylase (enzymes), you can't use the starchy adjuncts.
Just adding 2 row, is about the same as adding some extra extract.

-a.